Merge remote-tracking branch 'origin/main' into fix/2261-pad-budget

# Conflicts:
#	crates/effects/src/lib.rs

.github/workflows/windows-arm64.yml

@@ -29,7 +29,7 @@ permissions:
 jobs:
   windows-arm64:
     # Immutable supporting workflow revision until the new install contract lands upstream.
-    uses: storytold/craft-common-actions/.github/workflows/windows-arm64.yml@8bb4e5ab95443171104ad88113fe1ef9b0e5ce3f
+    uses: storytold/craft-common-actions/.github/workflows/windows-arm64.yml@fa5ef18780cf5e7d5d3b8de068de56cffc83cac5
     with:
       app-name: effectcraft
       app-dir: EffectCraft

Cargo.lock

@@ -1623,6 +1623,7 @@ name = "effectcraft-media"
 version = "0.18.0"
 dependencies = [
  "craft-docpath",
+ "effectcraft-color",
  "effectcraft-model",
  "effectcraft-pdf",
  "effectcraft-project",

README.md

@@ -84,9 +84,10 @@ a few places where it matters to us:
   without a plugin.
 - **A project file you can read.** Projects are versioned JSON (`.ecproj`), so they diff cleanly
   in version control.
-- **Everything is scriptable.** Every menu item, timeline drag and property edit goes through one
-  command registry, so the same actions are reachable from a command line, a JSON control
-  channel and an MCP server for agents.
+- **Everything is scriptable.** Menu actions, timeline edits and property changes are exposed as
+  commands. Engine commands are available through the CLI, JSON control channel and MCP;
+  UI-only commands use the frontend dispatcher and can be invoked through the control channel
+  or an attached MCP bridge.
 - **No FFmpeg.** Video and audio decoding and encoding are pure Rust: FilmCraft's codecs and
   EffectCraft's own VP9, AV1, HEVC and Opus encoders.
 
@@ -173,8 +174,10 @@ cannot express; File ▸ Import ▸ Lottie… opens one as a new composition.
 
 ## Built for agents
 
-Everything you can do from a menu is a command with an id, and agents can reach every one of
-them:
+Engine commands are available through the CLI, JSON control channel and MCP. UI-only commands
+need the running app's frontend dispatcher: complete menu access requires the app's control
+channel or an attached MCP bridge. Headless MCP sessions expose supported engine commands,
+but not UI-only commands or bridge-only `ui_*` tools.
 
 - **MCP server:** `effectcraft-cli mcp` speaks the Model Context Protocol over stdio, headless
   or bridged to the running app (`--bridge 9877`). Tools cover commands, the project and property

crates/automation/tests/qa/compositing.rs

@@ -35,7 +35,7 @@ fn import_footage(qa: &mut Qa) -> (Value, Value) {
     // Footage: the sequence, and a layered PSD written by the app itself (Save Frame As ▸
     // Photoshop Layers) from a small comp.
     let seq = write_sequence(qa);
-    let imp = qa.exec("file.import", json!({"paths": [seq]}));
+    let imp = qa.exec("file.import", json!({"paths": [seq], "sequence": true}));
     let seq_item = imp["items"][0].clone();
     let project = qa.tool("get_project", json!({}));
     let it = project["items"].as_array().unwrap().iter().find(|i| i["id"] == seq_item).unwrap().clone();

crates/automation/tests/qa/tracking.rs

@@ -52,7 +52,7 @@ fn shake_offset(f: u32) -> (i64, i64) {
 
 /// Import a sequence at 12 fps and make a comp of it; returns (comp, layer).
 fn plate_comp(qa: &mut Qa, first: &str, name: &str) -> (Value, Value) {
-    let item = qa.exec("file.import", json!({"paths": [first]}))["items"][0].clone();
+    let item = qa.exec("file.import", json!({"paths": [first], "sequence": true}))["items"][0].clone();
     qa.exec("file.interpretFootage", json!({"items": [item.clone()], "frameRate": 12}));
     let comp = qa.exec("comp.new", json!({"name": name, "width": 160, "height": 90, "frameRate": 12, "duration": 1}))["comp"].clone();
     let layer = qa.exec("layer.addItem", json!({"item": item}))["layer"].clone();

crates/effects/src/audio_fx.rs

@@ -206,6 +206,12 @@ pub fn reverses(id: &str) -> bool {
     id == "ec.audio.backwards"
 }
 
+/// Does each output sample depend only on the input sample at the same time (no state), so the
+/// mixer may run the effect in short pieces with parameters animated between them?
+pub fn per_sample(id: &str) -> bool {
+    matches!(id, "ec.audio.stereomixer" | "ec.audio.backwards")
+}
+
 /// Seconds of input history the effect needs before a block to reach the state it would have
 /// had when processing continuously.
 pub fn preroll(id: &str, params: &Params) -> f64 {

crates/effects/src/channel3d.rs

@@ -7,6 +7,11 @@
 //! pass for a precomp of a 3D comp. Without auxiliary channels they pass the layer through
 //! (EXtractoR still maps the layer's own R, G, B and A).
 //!
+//! 3D Layer Instance (Create 3D Layer Instance's own effect, Layer ▸ Create) is not an aux
+//! reader: it replaces the layer's pixels with a referenced layer's render — for a 3D model
+//! layer, its render on its own through the comp's camera — so 2D effects can be applied to a
+//! 3D layer's render.
+//!
 //! Aux pixels are looked up nearest-neighbour (IDs must not be interpolated) at each buffer
 //! pixel's layer position, so render scale and layer padding are respected.
 
@@ -582,6 +587,19 @@ fn extractor(ctx: &EffectCtx, mut b: Buf) -> Buf {
     b
 }
 
+/// A 2D copy of a referenced layer (Create 3D Layer Instance's solid): the layer's pixels
+/// replaced with the referenced layer's render, alpha included — the copy is transparent
+/// where the referenced layer isn't. A 3D model or primitive layer is rendered on its own
+/// through the comp's camera, as After Effects renders 3D layers; another layer is read with
+/// its masks and effects. With no layer chosen the effect passes the layer through, as a layer
+/// parameter with nothing chosen does.
+fn instance_3d(ctx: &EffectCtx, mut b: Buf) -> Buf {
+    if let Some(o) = ctx.layer_param("layer", true) {
+        b.img = crate::util::fit_layer(ctx, &b, &o, false);
+    }
+    b
+}
+
 pub fn specs() -> Vec<EffectSpec> {
     let text = |id: &'static str, name: &'static str, d: &str| p(id, name, Value::Str(d.into()), ParamUi::Text);
     vec![
@@ -682,6 +700,7 @@ pub fn specs() -> Vec<EffectSpec> {
             ],
             identifier,
         ),
+        spec("ec.3d.instance3d", "3D Layer Instance", vec![p("layer", "Layer", Value::Layer(None), ParamUi::Layer)], instance_3d),
     ]
 }
 

crates/effects/src/channel3d/tests.rs

@@ -373,3 +373,29 @@ fn channel_extract_antialias_averages_sub_pixels() {
     let soft = run("ec.3d.channelextract", &[vals.as_slice(), &[("antialias", Value::Bool(true))]].concat(), &host);
     assert!((soft.get(5, 5)[0] - 0.5).abs() < 1e-5, "{:?}", soft.get(5, 5));
 }
+
+#[test]
+fn instance3d_replaces_the_pixels_with_the_referenced_layer() {
+    // Create 3D Layer Instance's copy: the chosen layer's render takes the place of the layer's
+    // own pixels, alpha included — the copy is transparent where the referenced layer isn't —
+    // and with no layer chosen the layer passes through.
+    struct Host(Image);
+    impl EffectHost for Host {
+        fn layer(&self, id: u64, _: bool) -> Option<LayerPixels> {
+            (id == 7).then(|| LayerPixels { buf: Buf { img: self.0.clone(), offset: [0.0; 2], scale: 1.0 }, size: [self.0.width as f64, self.0.height as f64] })
+        }
+        fn audio(&self, _: u64, _: f64, _: usize, _: u32) -> Option<Vec<f32>> {
+            None
+        }
+    }
+    let solid = || Image::filled(4, 4, [1.0, 1.0, 1.0, 1.0]);
+    let mut render = Image::new(4, 4);
+    render.set(1, 1, [1.0, 0.0, 0.0, 1.0]);
+    let env = EffectEnv { host: Some(&Host(render)), ..Default::default() };
+    let out = run_fx("ec.3d.instance3d", &[("layer", Value::Layer(Some(7)))], solid(), 0.0, env);
+    assert_eq!(out.img.get(1, 1), [1.0, 0.0, 0.0, 1.0], "the referenced layer's pixel");
+    assert_eq!(out.img.get(3, 3), [0.0; 4], "transparent where the referenced layer isn't");
+    // No layer chosen: the layer's own pixels.
+    let out = run_fx("ec.3d.instance3d", &[], solid(), 0.0, EffectEnv::default());
+    assert_eq!(out.img.data, solid().data);
+}

crates/effects/src/lib.rs

@@ -312,15 +312,16 @@ impl Buf {
         self.offset[0] += l as f64;
         self.offset[1] += t as f64;
     }
-    /// Grow by `pad` transparent pixels on every side, within [`pad_within_budget`].
+    /// Grow by `pad` transparent pixels on every side, within [`pad_within_budget`] and as
+    /// clamped by [`Image::effective_pad`].
     pub fn pad(&mut self, pad: u32) {
-        let pad = pad_within_budget(self.img.width, self.img.height, pad);
-        if pad == 0 {
+        let eff = self.img.effective_pad(pad_within_budget(self.img.width, self.img.height, pad));
+        if eff == 0 {
             return;
         }
-        self.img = self.img.padded(pad);
-        self.offset[0] += pad as f64;
-        self.offset[1] += pad as f64;
+        self.img = self.img.padded(eff);
+        self.offset[0] += eff as f64;
+        self.offset[1] += eff as f64;
     }
 }
 
@@ -1384,6 +1385,20 @@ mod tests {
         assert_eq!(out.img.data, img.data);
     }
 
+    #[test]
+    fn pad_offset_follows_the_clamped_pad() {
+        // Image::padded clamps a hostile pad to keep each side within MAX_PADDED_SIDE; the offset
+        // must move by the pad actually applied, or the content drifts from its layer position.
+        let mut img = Image::new(29_990, 2);
+        img.set(0, 0, [1.0, 0.0, 0.0, 1.0]);
+        let mut buf = Buf { img, offset: [3.0, 4.0], scale: 1.0 };
+        buf.pad(u32::MAX);
+        // Width binds: (MAX_PADDED_SIDE - 29 990) / 2 = 5.
+        assert_eq!(buf.offset, [8.0, 9.0]);
+        let (x, y) = buf.to_px([-3.0, -4.0]);
+        assert_eq!(buf.img.get(x as i64, y as i64), [1.0, 0.0, 0.0, 1.0]);
+    }
+
     #[test]
     #[ignore]
     fn dump_registry() {

crates/engine/src/analysis/tracking.rs

@@ -207,7 +207,7 @@ pub(crate) fn source_frame(
     t: Tick,
     expr: Option<&dyn ExprHost>,
 ) -> Option<(Arc<Image>, [f64; 2])> {
-    let ctx = EvalCtx { project, comp_id: cid, comp, time: t, expr, footage: None };
+    let ctx = EvalCtx { project, comp_id: cid, comp, time: t, expr, footage: None, property_overrides: &[], media_overrides: &[] };
     if let effectcraft_project::LayerSource::Footage { item } = &layer.source
         && let Some(effectcraft_project::ItemKind::Footage(f)) = project.item(*item).map(|i| &i.kind)
         && f.has_video

crates/engine/src/cmd/create.rs

@@ -1,14 +1,17 @@
 //! Layer ▸ Create: Convert to Editable Text (Photoshop type layers), Create Shapes from Text,
-//! Create Masks from Text and Create Shapes from Vector Layer (SVG footage).
+//! Create Masks from Text, Create Shapes from Vector Layer (SVG footage) and Create 3D Layer
+//! Instance (a 2D copy of a 3D model layer that 2D effects can be applied to).
 
 use effectcraft_color::Label;
+use effectcraft_keyframe::Value as KV;
+use effectcraft_project::build::{self, Ids};
 use effectcraft_project::{ItemKind, LayerSource, Solid};
 use serde_json::{Value, json};
 
 use super::{CommandSpec, bad, has_layers, layers_p, str_p};
 use crate::{EngineError, Result, Session, cmd};
 
-const OPS: &str = "editableText|shapesFromText|masksFromText|shapesFromVector";
+const OPS: &str = "editableText|shapesFromText|masksFromText|shapesFromVector|instance3d";
 
 fn create(s: &mut Session, p: &Value) -> Result<Value> {
     let op = str_p(p, "op").ok_or_else(|| bad("layer.create", format!("missing `op` ({OPS})")))?;
@@ -19,6 +22,69 @@ fn create(s: &mut Session, p: &Value) -> Result<Value> {
     let time = s.time();
     let mut created = vec![];
     let mut skipped = vec![];
+    // All the selected models in one edit: one undo (or redo) removes (or restores) every
+    // instance at once, as one command in the History panel.
+    if op == "instance3d" {
+        // After Effects' Create 3D Layer Instance (Layer ▸ Create): 3D model layers take
+        // no masks or effects, so a comp-sized solid goes at the top of the layer stack
+        // with a 3D Layer Instance effect referencing the model — a 2D copy of its render,
+        // through the comp's camera, that 2D effects can be applied to. The model is switched
+        // off, as After Effects does (back on to keep its shadow).
+        let comp = s.project.comp(cid).ok_or(EngineError::NoComp)?.clone();
+        let mut eligible = vec![];
+        for lid in &lids {
+            match comp.layer(*lid) {
+                Some(src) if src.source.is_model() => eligible.push((*lid, src.clone())),
+                Some(src) => skipped.push(format!("{}: not a 3D model layer", src.name)),
+                None => {}
+            }
+        }
+        if !eligible.is_empty() {
+            let ids = s.edit("Create 3D Layer Instance", None, |proj, st| {
+                let mut ids = vec![];
+                for (lid, src) in &eligible {
+                    let name = proj.comp(cid).ok_or(EngineError::NoComp)?.unique_layer_name(&format!("{} Instance", src.name));
+                    let folder = proj.folder_named("Solids").unwrap_or_else(|| proj.add_item("Solids", Label::Yellow, None, ItemKind::Folder));
+                    let sid = proj.add_item(
+                        &name,
+                        src.label,
+                        Some(folder),
+                        ItemKind::Solid(Solid { color: [1.0, 1.0, 1.0], width: comp.width, height: comp.height, pixel_aspect: 1.0 }),
+                    );
+                    let mut l = build::layer(proj, &comp, &name, LayerSource::Solid { item: sid }, (comp.width, comp.height), None);
+                    // A soloed source keeps its Solo switch with video off, and any_solo hides
+                    // the non-soloed copy: the copy takes the Solo over to stay visible.
+                    l.switches.solo = src.switches.solo;
+                    // A 3D Layer Instance effect referencing the 3D layer: the solid shows its
+                    // render (the 2D copy).
+                    let fx = effectcraft_effects::find("ec.3d.instance3d").ok_or_else(|| bad("layer.create", "the 3D Layer Instance effect is missing"))?;
+                    let mut g = effectcraft_effects::instantiate(fx, &mut Ids(&mut proj.next_id), fx.name, [comp.width as f64, comp.height as f64]);
+                    if let Some(pr) = g.get_mut("layer") {
+                        pr.value = KV::Layer(Some(lid.0));
+                    }
+                    if let Some(fxg) = l.props.sub_mut("effects") {
+                        fxg.children.push(g.into());
+                    }
+                    // The model is switched off (After Effects turns the referenced layer off);
+                    // the copies go at the top of the stack, selected.
+                    let c = proj.comp_mut(cid).ok_or(EngineError::NoComp)?;
+                    if let Some(m) = c.layers.iter_mut().find(|x| x.id == *lid) {
+                        m.switches.video = false;
+                    }
+                    let id = l.id;
+                    c.layers.insert(0, l);
+                    ids.push(id);
+                }
+                st.selected_layers = ids.clone();
+                Ok(ids)
+            })?;
+            created.extend(ids.iter().map(|i| i.0));
+        }
+        if created.is_empty() && !skipped.is_empty() {
+            return Err(bad("layer.create", skipped.join("; ")));
+        }
+        return Ok(json!({"layers": created, "skipped": skipped}));
+    }
     for lid in lids {
         let comp = s.project.comp(cid).ok_or(EngineError::NoComp)?.clone();
         let Some(src) = comp.layer(lid).cloned() else { continue };
@@ -198,5 +264,5 @@ fn insert_above(
 }
 
 pub fn specs() -> Vec<CommandSpec> {
-    vec![cmd!("layer.create", "Create", [], None, "{op: editableText|shapesFromText|masksFromText|shapesFromVector, layers?}", has_layers, create)]
+    vec![cmd!("layer.create", "Create", [], None, "{op: editableText|shapesFromText|masksFromText|shapesFromVector|instance3d, layers?}", has_layers, create)]
 }

crates/engine/src/cmd/edit.rs

@@ -146,6 +146,11 @@ fn duplicate(s: &mut Session, p: &Value) -> Result<Value> {
         st.selected_layers = created.clone();
         Ok(created)
     })?;
+    // Duplicating selects the copies, so an open text edit on a now-deselected layer ends
+    // (#2226): typing must not keep editing an unselected layer.
+    if s.state.text_edit.as_ref().is_some_and(|e| !s.state.selected_layers.contains(&e.layer)) {
+        super::text_edit::end_edit(s, &Value::Null)?;
+    }
     Ok(json!(new.iter().map(|l| l.0).collect::<Vec<_>>()))
 }
 

crates/engine/src/cmd/effect.rs

@@ -136,7 +136,16 @@ fn warning(s: &mut Session, p: &Value) -> Result<Value> {
     let layer = comp.layer(lid).ok_or(EngineError::NoComp)?;
     let g = layer.effects().and_then(|fx| fx.groups().find(|g| g.uid == uid)).ok_or_else(|| bad(cmd, "no such effect"))?;
     let t = super::time_p(s, p, Some(comp));
-    let ctx = effectcraft_render::EvalCtx { project: &s.project, comp_id: cid, comp, time: t, expr: s.expr.as_deref(), footage: None };
+    let ctx = effectcraft_render::EvalCtx {
+        project: &s.project,
+        comp_id: cid,
+        comp,
+        time: t,
+        expr: s.expr.as_deref(),
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     Ok(json!({"effect": uid, "warning": effectcraft_effects::warning(g, &mut |pr| ctx.value(layer, pr))}))
 }
 
@@ -160,7 +169,16 @@ fn pick_color(s: &mut Session, p: &Value) -> Result<Value> {
     .filter(|pr| pr.ui == effectcraft_project::ParamUi::Color)
     .ok_or_else(|| bad(cmd, "not a colour parameter of this effect"))?;
     let t = super::time_p(s, p, Some(comp));
-    let ctx = effectcraft_render::EvalCtx { project: &s.project, comp_id: cid, comp, time: t, expr: s.expr.as_deref(), footage: None };
+    let ctx = effectcraft_render::EvalCtx {
+        project: &s.project,
+        comp_id: cid,
+        comp,
+        time: t,
+        expr: s.expr.as_deref(),
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let mut r = effectcraft_render::Renderer::new(&s.project, &*s.footage, effectcraft_render::RenderOpts::default());
     r.expr = s.expr.as_deref();
     r.cache = Some(&s.layer_cache);
@@ -288,7 +306,16 @@ impl CryptoProbe {
             let comp = r.project.comp(cid).ok_or("no composition")?;
             let layer = comp.layer(lid).ok_or("no such layer")?;
             let g = layer.effects().and_then(|fx| fx.groups().nth(pos)).ok_or("no such effect")?;
-            let ctx = effectcraft_render::EvalCtx { project: r.project, comp_id: cid, comp, time, expr: r.expr, footage: None };
+            let ctx = effectcraft_render::EvalCtx {
+                project: r.project,
+                comp_id: cid,
+                comp,
+                time,
+                expr: r.expr,
+                footage: None,
+                property_overrides: &[],
+                media_overrides: &[],
+            };
             let params = effectcraft_effects::flatten_params(g, &mut |pr| ctx.value(layer, pr));
             let want = effectcraft_effects::CRYPTO_LAYERS.get(params.e("layer") as usize).copied().unwrap_or("CryptoAsset");
             let aux = r.layer_aux(&ctx, layer).ok_or(NO_CRYPTO)?;
@@ -351,7 +378,16 @@ fn probe_key<'a>(s: &'a Session, p: &Value, cmd: &str) -> Result<(ProbeKey, Tick
     let g = fx.groups().nth(pos).ok_or_else(|| bad(cmd, "no such effect"))?;
     let prop = g.prop("selection").filter(|_| g.match_id == "ec.3d.cryptomatte").ok_or_else(|| bad(cmd, "not a Cryptomatte effect"))?;
     let time = super::time_p(s, p, Some(comp));
-    let ctx = effectcraft_render::EvalCtx { project: &s.project, comp_id: cid, comp, time, expr: s.expr.as_deref(), footage: None };
+    let ctx = effectcraft_render::EvalCtx {
+        project: &s.project,
+        comp_id: cid,
+        comp,
+        time,
+        expr: s.expr.as_deref(),
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let frame = probe_frame(&ctx, layer, pos);
     let o = s.render_opts(Default::default());
     let prefs = (o.nested_switches, o.draft_shadows);
@@ -503,7 +539,16 @@ fn crypto_hit(s: &Session, p: &Value, cmd: &str) -> Result<Hit> {
     let Some(hash) = b.aux.index_at(ax, ay).and_then(|i| b.aux.crypto_id_at(&b.layer, i)) else { return Ok(Hit::Nothing) };
     let (cid, lid, ..) = key.at;
     let comp = s.project.comp(cid).ok_or(EngineError::NoComp)?;
-    let ctx = effectcraft_render::EvalCtx { project: &s.project, comp_id: cid, comp, time, expr: s.expr.as_deref(), footage: None };
+    let ctx = effectcraft_render::EvalCtx {
+        project: &s.project,
+        comp_id: cid,
+        comp,
+        time,
+        expr: s.expr.as_deref(),
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let selection = effectcraft_effects::flatten_params(g, &mut |pr| ctx.value(layer, pr)).s("selection").to_string();
     let driven = prop.expr.as_ref().is_some_and(|e| e.enabled);
     let (aux, layer_name) = (b.aux.clone(), b.layer.clone());

crates/engine/src/cmd/expr_tools.rs

@@ -163,6 +163,8 @@ pub fn language_menu() -> Vec<(&'static str, Vec<(&'static str, &'static str)>)>
                 ("easeIn(t, tMin, tMax, value1, value2)", "easeIn(t, tMin, tMax, value1, value2)"),
                 ("easeOut(t, value1, value2)", "easeOut(t, value1, value2)"),
                 ("easeOut(t, tMin, tMax, value1, value2)", "easeOut(t, tMin, tMax, value1, value2)"),
+                ("bezier(t, value1, value2, [x1, y1, x2, y2])", "bezier(t, value1, value2, [x1, y1, x2, y2])"),
+                ("bezier(t, tMin, tMax, value1, value2, [x1, y1, x2, y2])", "bezier(t, tMin, tMax, value1, value2, [x1, y1, x2, y2])"),
             ],
         ),
         (

crates/engine/src/cmd/file_more.rs

@@ -878,10 +878,34 @@ fn replace_footage(s: &mut Session, p: &Value) -> Result<Value> {
     let path = str_p(p, "path").ok_or_else(|| bad("file.replaceFootage", "missing `path`"))?.to_string();
     let item = *items_p(s, p).first().ok_or_else(|| bad("file.replaceFootage", "select footage"))?;
     let importer = s.importer.clone().ok_or_else(|| EngineError::Other("media import is not available in this build".into()))?;
-    // A numbered still brings its image sequence, as on import (`sequence: false` for one frame).
-    let opts = SequenceOptions::from_params(p);
+    // Replacing a still keeps it a still; replacing a sequence keeps bringing the new file's run.
+    // `sequence`/`alphabetical` override that (#2073).
+    let previous = match s.project.item(item).map(|it| &it.kind) {
+        Some(ItemKind::Footage(f)) if f.kind == FootageKind::Sequence => (true, true, f.alphabetical),
+        _ => (false, false, false),
+    };
+    // Only `sequence` decides whether the item keeps its kind; `alphabetical` is a sequence
+    // modifier, not a request to make one.
+    let inherited = b_p(p, "sequence").is_none();
+    let mut opts = SequenceOptions::from_params(p);
+    if inherited {
+        (opts.sequence, opts.folders) = (previous.0, previous.1);
+        if previous.0 && b_p(p, "alphabetical").is_none() {
+            opts.alphabetical = previous.2;
+        }
+    }
     let src = crate::sequence::source_of(s.services.as_ref(), &path, opts);
-    let f = crate::sequence::probe(importer.as_ref(), &src, s.sequence_rate()).map_err(|e| EngineError::Other(format!("{path}: {e}")))?;
+    let mut f = crate::sequence::probe(importer.as_ref(), &src, s.sequence_rate()).map_err(|e| EngineError::Other(format!("{path}: {e}")))?;
+    // A single-file source comes back as a still; an inherited sequence kind keeps it a
+    // one-frame sequence, so a later default replacement still brings numbered runs (#2073).
+    if inherited && previous.0 && matches!(src, crate::sequence::Source::File(_)) && f.kind == FootageKind::Still {
+        f.kind = FootageKind::Sequence;
+        f.sequence = vec![f.path.clone()];
+        f.alphabetical = opts.alphabetical;
+        f.frame_rate = s.sequence_rate();
+        f.native_rate = None;
+        f.sync_sequence_duration();
+    }
     let name = src.name();
     // Replacing a missing file relinks the other missing files that moved with it (as After Effects
     // does when you locate one).
@@ -1093,7 +1117,7 @@ pub fn specs() -> Vec<CommandSpec> {
             "File...",
             ["File", "Replace Footage"],
             Some("Cmd+H"),
-            "{path, item?, sequence?: bool (default true: a numbered still brings its image sequence), alphabetical?: bool}",
+            "{path, item?, sequence?: bool (a numbered still brings its image sequence; default: the item keeps its kind, so a still stays a still and a sequence stays a sequence), alphabetical?: bool}",
             has_footage_selection,
             replace_footage
         ),

crates/engine/src/cmd/focus.rs

@@ -78,6 +78,12 @@ fn set_to_layer(s: &mut Session, p: &Value) -> Result<Value> {
     let c = "camera.setFocusToLayer";
     let (cid, cam, target) = refs(s, p, c, true)?;
     let d = focus_depth(s, cid, cam, target.ok_or_else(|| bad(c, "no layer"))?).ok_or_else(|| bad(c, "can't evaluate the layers"))?;
+    // Only a finite depth can be stored: JSON has no infinity or NaN, so the project could no
+    // longer be saved. Extreme but finite positions can still produce one, and `d <= 0.0` is
+    // false for NaN.
+    if !d.is_finite() {
+        return Err(bad(c, "can't measure the distance to the layer (the camera or layer position is out of range)"));
+    }
     if d <= 0.0 {
         return Err(bad(c, "the layer is behind the camera"));
     }

crates/engine/src/cmd/layer/parent.rs

@@ -9,10 +9,20 @@ pub(crate) struct ParentFix {
     rotation: f64,
     /// Multiply Scale.
     scale: [f64; 2],
-    /// 3D AV layers retain their world-space anchor, including Z.
+    /// 3D AV layers retain their world-space anchor, including Z. Cameras and lights also
+    /// re-express their Point of Interest.
     position_3d: Option<effectcraft_geom::Mat4>,
-    /// A uniform relative parent transform can preserve static Orientation and Scale.
-    pose_3d: Option<([f64; 3], f64)>,
+    /// A uniform relative parent transform re-expresses static Orientation and Scale.
+    pose_3d: Option<Pose3d>,
+}
+
+/// A uniform relative parent transform, as it applies to a 3D layer's Orientation and Scale.
+#[derive(Clone, Copy)]
+struct Pose3d {
+    /// Rotation that Orientation is re-expressed under: `Orientation' = correction * Orientation`.
+    correction: effectcraft_geom::Mat4,
+    /// Uniform scale factor, multiplied into Scale (negative for a mirrored parent).
+    factor: f64,
 }
 
 impl ParentFix {
@@ -22,7 +32,7 @@ impl ParentFix {
         if let Some(m) = self.position_3d {
             // Spatial Position speed measures distance along its path. Its parent-space
             // unit changes even when the child's Orientation cannot be re-expressed.
-            let position_speed = uniform_parent_pose(m, [0.0; 3]).map(|(_, factor)| factor.abs());
+            let position_speed = uniform_rotation(m).map(|(_, factor)| factor.abs());
             let map_position = |v: &KV| {
                 let q = m.apply(effectcraft_geom::Vec3::from(v.as_vec3()));
                 KV::Vec3([q.x, q.y, q.z])
@@ -44,7 +54,8 @@ impl ParentFix {
                     }
                 }
             }
-            if let Some(pr) = tr.get_mut("position") {
+            // Position and a camera's or light's Point of Interest are both points in the parent's space.
+            let map_point = |pr: &mut effectcraft_project::Property| {
                 pr.value = map_position(&pr.value);
                 for key in &mut pr.keys {
                     key.value = map_position(&key.value);
@@ -64,34 +75,19 @@ impl ParentFix {
                         }
                     }
                 }
+            };
+            if let Some(pr) = tr.get_mut("position") {
+                map_point(pr);
             }
-            // Cameras and lights aim with Point of Interest: move it by the same parent-space
-            // change, so a two-node rig keeps its world frame (#1010, #1020).
             if let Some(pr) = tr.get_mut("poi") {
-                pr.value = map_position(&pr.value);
-                for key in &mut pr.keys {
-                    key.value = map_position(&key.value);
-                    for tangent in [&mut key.spatial_in, &mut key.spatial_out] {
-                        let v = m.apply_vec(effectcraft_geom::Vec3::from(*tangent));
-                        *tangent = [v.x, v.y, v.z];
-                    }
-                }
-                if let Some(factor) = position_speed
-                    .filter(|_| pr.spatial)
-                    .filter(|factor| pr.keys.iter().flat_map(|key| key.in_ease.iter().chain(&key.out_ease)).all(|ease| (ease.speed * *factor).is_finite()))
-                {
-                    for key in &mut pr.keys {
-                        for ease in key.in_ease.iter_mut().chain(&mut key.out_ease) {
-                            ease.speed *= factor;
-                        }
-                    }
-                }
+                map_point(pr);
             }
-            if let Some((orientation, factor)) = self.pose_3d {
+            if let Some(pose) = self.pose_3d {
                 if let Some(pr) = tr.get_mut("orientation") {
-                    pr.value = KV::Vec3(orientation);
+                    reexpress_orientation(pose.correction, pr);
                 }
                 if let Some(pr) = tr.get_mut("scale") {
+                    let factor = pose.factor;
                     let scaled = |value: &KV| KV::Vec3(value.as_vec3().map(|v| v * factor));
                     pr.value = scaled(&pr.value);
                     for key in &mut pr.keys {
@@ -154,13 +150,10 @@ impl ParentFix {
     }
 }
 
-/// A uniform factor commutes with authored axis Rotation and Scale; prepend its orthogonal
-/// rotation to static Orientation using the existing Rz * Ry * Rx order.
-fn uniform_parent_pose(m: effectcraft_geom::Mat4, orientation: [f64; 3]) -> Option<([f64; 3], f64)> {
-    use effectcraft_geom::{Mat4, Vec3, vec3};
-    if !orientation.iter().all(|v| v.is_finite()) {
-        return None;
-    }
+/// The rotation and signed scale factor of a uniform parent transform's linear part (negative for a
+/// mirrored parent). `None` for a non-uniform or degenerate transform.
+fn uniform_rotation(m: effectcraft_geom::Mat4) -> Option<(effectcraft_geom::Mat4, f64)> {
+    use effectcraft_geom::{Mat4, vec3};
     let a = m.0;
     let columns = [vec3(a[0][0], a[1][0], a[2][0]), vec3(a[0][1], a[1][1], a[2][1]), vec3(a[0][2], a[1][2], a[2][2])];
     let magnitude = columns[0].x.hypot(columns[0].y).hypot(columns[0].z);
@@ -179,15 +172,188 @@ fn uniform_parent_pose(m: effectcraft_geom::Mat4, orientation: [f64; 3]) -> Opti
             rotation.0[row][col] = a[row][col] / factor;
         }
     }
-    if (0..3).all(|row| (0..3).all(|col| (rotation.0[row][col] - if row == col { 1.0 } else { 0.0 }).abs() < 1e-12)) {
-        return Some((orientation, factor));
-    }
-    let r = (rotation * Mat4::orientation(Vec3::from(orientation))).0;
+    Some((rotation, factor))
+}
+
+/// The turn (degrees) of a rotation about Z alone, or `None` for any other rotation.
+fn z_only_turn(correction: effectcraft_geom::Mat4) -> Option<f64> {
+    let m = correction.0;
+    let about_z = [m[0][2], m[1][2], m[2][0], m[2][1]].iter().all(|v| v.abs() < 1e-9) && (m[2][2] - 1.0).abs() < 1e-9;
+    about_z.then(|| m[1][0].atan2(m[0][0]).to_degrees())
+}
+
+/// ZYX Euler angles in degrees of a row-major rotation (`Rz * Ry * Rx`), safe at gimbal lock.
+fn euler_zyx(r: [[f64; 4]; 4]) -> [f64; 3] {
     // atan2 rather than asin: near ±90 degrees asin loses precision, while cos(y) stays exact.
     let cy = r[0][0].hypot(r[1][0]);
     let y = (-r[2][0]).atan2(cy);
     let (x, z) = if cy > 1e-9 { (r[2][1].atan2(r[2][2]), r[1][0].atan2(r[0][0])) } else { ((-r[1][2]).atan2(r[1][1]), 0.0) };
-    Some(([x.to_degrees(), y.to_degrees(), z.to_degrees()], factor))
+    [x.to_degrees(), y.to_degrees(), z.to_degrees()]
+}
+
+/// The equivalent ZYX Euler triple nearest `reference`: each axis moved by whole turns, or the
+/// `(x + 180, 180 - y, z + 180)` form when that is nearer.
+fn nearest_euler(euler: [f64; 3], reference: [f64; 3]) -> [f64; 3] {
+    let near = |v: [f64; 3]| -> [f64; 3] { std::array::from_fn(|i| v[i] + ((reference[i] - v[i]) / 360.0).round() * 360.0) };
+    let natural = near(euler);
+    let flipped = near([euler[0] + 180.0, 180.0 - euler[1], euler[2] + 180.0]);
+    let distance = |v: [f64; 3]| v.iter().zip(reference.iter()).map(|(a, b)| (a - b).powi(2)).sum::<f64>();
+    if distance(flipped) < distance(natural) { flipped } else { natural }
+}
+
+/// The Euler Orientation of `correction * Orientation(o)`, in the form nearest `reference`.
+fn reexpress_euler(correction: effectcraft_geom::Mat4, o: [f64; 3], reference: [f64; 3]) -> [f64; 3] {
+    let world = correction * effectcraft_geom::Mat4::orientation(effectcraft_geom::Vec3::from(o));
+    nearest_euler(euler_zyx(world.0), reference)
+}
+
+/// Largest angle (degrees) a baked Orientation may drift from the exact rotation between its keys.
+const BAKE_TOLERANCE_DEGREES: f64 = 0.05;
+/// How many times a segment may be halved while baking, and the most keys a property may end up with.
+const BAKE_MAX_DEPTH: u32 = 10;
+const BAKE_MAX_KEYS: usize = 4096;
+
+/// The angle (degrees) between two rotations.
+fn rotation_angle(a: effectcraft_geom::Mat4, b: effectcraft_geom::Mat4) -> f64 {
+    let trace: f64 = (0..3).flat_map(|i| (0..3).map(move |j| (i, j))).map(|(i, j)| a.0[i][j] * b.0[i][j]).sum();
+    ((trace - 1.0) / 2.0).clamp(-1.0, 1.0).acos().to_degrees()
+}
+
+/// Adds keys between `(ta, ea)` and `(tb, eb)` (already converted) wherever the straight Euler blend
+/// between them drifts from `correction * Orientation(authored)` by more than the tolerance. `out`
+/// never grows past `budget` keys: what the whole property may still add, not what one segment may.
+fn bake_between(
+    correction: effectcraft_geom::Mat4,
+    authored: &effectcraft_project::Property,
+    (ta, ea): (Tick, [f64; 3]),
+    (tb, eb): (Tick, [f64; 3]),
+    depth: u32,
+    budget: usize,
+    out: &mut Vec<effectcraft_keyframe::Keyframe>,
+) {
+    use effectcraft_geom::{Mat4, Vec3};
+    if depth == 0 || tb.0 - ta.0 < 2 || out.len() >= budget {
+        return;
+    }
+    let tm = Tick(ta.0 + (tb.0 - ta.0) / 2);
+    let blend = [(ea[0] + eb[0]) / 2.0, (ea[1] + eb[1]) / 2.0, (ea[2] + eb[2]) / 2.0];
+    let exact = correction * Mat4::orientation(Vec3::from(authored.value_at(tm).as_vec3()));
+    // Symmetric easing crosses the straight blend at its midpoint. Check both sides too before
+    // accepting a segment whose original easing will be replaced with a linear blend.
+    let quarter = (tb.0 - ta.0) / 4;
+    if [Tick(ta.0 + quarter), tm, Tick(tb.0 - quarter)].into_iter().all(|t| {
+        let u = (t.0 - ta.0) as f64 / (tb.0 - ta.0) as f64;
+        let linear = std::array::from_fn(|i| ea[i] + (eb[i] - ea[i]) * u);
+        let target = correction * Mat4::orientation(Vec3::from(authored.value_at(t).as_vec3()));
+        rotation_angle(Mat4::orientation(Vec3::from(linear)), target) <= BAKE_TOLERANCE_DEGREES
+    }) {
+        return;
+    }
+    let em = nearest_euler(euler_zyx(exact.0), blend);
+    bake_between(correction, authored, (ta, ea), (tm, em), depth - 1, budget, out);
+    if out.len() >= budget {
+        return;
+    }
+    out.push(effectcraft_keyframe::Keyframe::new(tm, KV::Vec3(em)));
+    bake_between(correction, authored, (tm, em), (tb, eb), depth - 1, budget, out);
+}
+
+/// Re-expresses Orientation as `correction * Orientation`. A Z-only correction shifts Z exactly in the
+/// value and every key. For any other correction a static value is converted directly; keys are
+/// converted, and keys are added between them wherever the Euler blend between two keys would drift
+/// from the exact rotation (the segments become linear, with the original easing baked in).
+fn reexpress_orientation(correction: effectcraft_geom::Mat4, pr: &mut effectcraft_project::Property) {
+    if let Some(turn) = z_only_turn(correction) {
+        // No turn (an identity correction) leaves every authored value as it is.
+        if turn.abs() <= 1e-12 {
+            return;
+        }
+        let shift = |value: &KV| {
+            let [x, y, z] = value.as_vec3();
+            KV::Vec3([x, y, z + turn])
+        };
+        pr.value = shift(&pr.value);
+        for key in &mut pr.keys {
+            key.value = shift(&key.value);
+        }
+        return;
+    }
+    let value = pr.value.as_vec3();
+    pr.value = KV::Vec3(reexpress_euler(correction, value, value));
+    if pr.keys.is_empty() {
+        return;
+    }
+    let authored = pr.clone();
+    // Each key keeps the authored change from the previous key on top of its converted value.
+    let mut converted: Vec<[f64; 3]> = vec![];
+    let mut prev: Option<([f64; 3], [f64; 3])> = None;
+    for key in &authored.keys {
+        let o = key.value.as_vec3();
+        let reference = match prev {
+            Some((before, after)) => [after[0] + o[0] - before[0], after[1] + o[1] - before[1], after[2] + o[2] - before[2]],
+            None => o,
+        };
+        let n = reexpress_euler(correction, o, reference);
+        converted.push(n);
+        prev = Some((o, n));
+    }
+    use effectcraft_keyframe::Interp;
+    let mut keys: Vec<effectcraft_keyframe::Keyframe> = vec![];
+    let mut after_baked_segment = false;
+    for (i, key) in authored.keys.iter().enumerate() {
+        let mut k = key.clone();
+        k.value = KV::Vec3(converted[i]);
+        if after_baked_segment {
+            k.in_interp = Interp::Linear;
+            k.in_ease.clear();
+            k.auto_bezier = false;
+            k.continuous = false;
+        }
+        after_baked_segment = false;
+        let segment = authored.keys.get(i + 1).filter(|_| key.out_interp != Interp::Hold);
+        let mut between = vec![];
+        if let Some(next) = segment {
+            // What the whole property may still add: the keys it will have already (the ones written
+            // and the authored ones still to come) count against the cap.
+            let budget = BAKE_MAX_KEYS.saturating_sub(keys.len() + authored.keys.len() - i);
+            bake_between(correction, &authored, (key.time, converted[i]), (next.time, converted[i + 1]), BAKE_MAX_DEPTH, budget, &mut between);
+            // With the cap reached the segment can't be checked or subdivided: it keeps its authored easing between
+            // the converted keys, rather than becoming a straight blend that was never checked against the original.
+            if between.len() >= budget {
+                between.clear();
+            // An eased segment, or one that gained keys, becomes a run of straight blends.
+            } else if !between.is_empty() || key.out_interp != Interp::Linear || next.in_interp != Interp::Linear {
+                k.out_interp = Interp::Linear;
+                k.out_ease.clear();
+                k.auto_bezier = false;
+                k.continuous = false;
+                after_baked_segment = true;
+            }
+        }
+        keys.push(k);
+        keys.extend(between);
+    }
+    pr.keys = keys;
+}
+
+/// Correction for a two-node rig's Orientation: after a uniform parent change its aim is
+/// `rotation * aim`, so the roll is re-expressed against that aim. `None` for a degenerate aim.
+fn aim_correction(rotation: effectcraft_geom::Mat4, aim: [f64; 3]) -> Option<effectcraft_geom::Mat4> {
+    use effectcraft_geom::vec3;
+    use effectcraft_render::three_d::camera::basis_rotation;
+    let [x, y, z] = aim;
+    let length = (x * x + y * y + z * z).sqrt();
+    if !length.is_finite() || length <= 1e-9 {
+        return None;
+    }
+    let dir = vec3(x / length, y / length, z / length);
+    let turned = rotation.apply_vec(dir);
+    // A view along the up axis has no roll to keep, and its basis is undefined.
+    if 1.0 - dir.y * dir.y < 1e-12 || 1.0 - turned.y * turned.y < 1e-12 {
+        return None;
+    }
+    let up = vec3(0.0, 1.0, 0.0);
+    Some(basis_rotation(turned, up).transpose() * rotation * basis_rotation(dir, up))
 }
 
 /// A parent change retains 2D transforms and the world-space anchor of 3D layers (Position,
@@ -196,8 +362,16 @@ fn uniform_parent_pose(m: effectcraft_geom::Mat4, orientation: [f64; 3]) -> Opti
 /// time.
 pub(crate) fn parent_fixes(s: &Session, cid: ItemId, ids: &[LayerId], parent: Option<LayerId>) -> Vec<ParentFix> {
     let Some(comp) = s.project.comp(cid) else { return vec![] };
-    let ectx =
-        effectcraft_render::EvalCtx { project: &s.project, comp_id: cid, comp, time: s.time(), expr: s.expr.as_deref(), footage: Some(s.footage.as_ref()) };
+    let ectx = effectcraft_render::EvalCtx {
+        project: &s.project,
+        comp_id: cid,
+        comp,
+        time: s.time(),
+        expr: s.expr.as_deref(),
+        footage: Some(s.footage.as_ref()),
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let space = |id: Option<LayerId>| -> effectcraft_geom::Mat3 {
         id.and_then(|i| comp.layer(i)).filter(|l| !l.is_3d()).map(|l| ectx.layer_to_comp(l).0).unwrap_or(effectcraft_geom::Mat3::IDENTITY)
     };
@@ -235,31 +409,58 @@ pub(crate) fn parent_fixes(s: &Session, cid: ItemId, ids: &[LayerId], parent: Op
         })
     };
     if let Some(inv) = space_3d(parent).inverse().filter(|m| m.0.iter().flatten().all(|v| v.is_finite())) {
-        // Cameras and lights compensate like 3D layers (Position, and Point of Interest for
-        // two-node rigs), so parenting keeps the world frame (#1010, #1020). They have no
-        // Scale, so `pose_3d` below stays `None` and Orientation is kept as authored.
         for layer in comp.layers.iter().filter(|l| ids.contains(&l.id) && l.is_3d() && l.parent != parent) {
             let m = inv * space_3d(layer.parent);
+            // A one-node camera or light has no Scale to carry a mirror, and its frame (forward and
+            // down) would come out reversed: compensate none of it, so Position and Orientation stay
+            // as authored instead of half-following the parent.
+            let rig = layer.is_camera() || layer.is_light();
+            if rig && !effectcraft_render::three_d::camera::is_two_node(layer) && uniform_rotation(m).is_some_and(|(_, factor)| factor <= 0.0) {
+                continue;
+            }
             if m.0.iter().flatten().all(|v| v.is_finite()) {
                 let pose_3d = layer.transform().and_then(|tr| {
                     let orientation = tr.get("orientation")?;
-                    let scale = tr.get("scale")?;
-                    // Animated Euler Orientation and auto-orient cannot be re-expressed by
-                    // prepending a constant Euler value. Expression-driven values stay authored.
-                    if !orientation.keys.is_empty()
-                        || orientation.expr.is_some()
-                        || scale.expr.is_some()
-                        || layer.auto_orient != effectcraft_project::AutoOrient::Off
+                    // Cameras and lights have no Scale; their Orientation is re-expressed alone.
+                    let scale = tr.get("scale");
+                    // Expression-driven values stay authored. Auto-orient replaces Orientation, except
+                    // a two-node rig, whose roll is re-expressed against its new aim.
+                    let two_node = (layer.is_camera() || layer.is_light()) && effectcraft_render::three_d::camera::is_two_node(layer);
+                    if orientation.expr.is_some()
+                        || scale.is_some_and(|scale| scale.expr.is_some())
+                        || (layer.auto_orient != effectcraft_project::AutoOrient::Off && !two_node)
                     {
                         return None;
                     }
-                    let pose = uniform_parent_pose(m, orientation.value.as_vec3())?;
-                    let factor = pose.1;
-                    let values_finite = std::iter::once(&scale.value)
-                        .chain(scale.keys.iter().map(|key| &key.value))
-                        .all(|value| value.as_vec3().iter().all(|v| (v * factor).is_finite()));
-                    let speeds_finite = scale.keys.iter().flat_map(|key| key.in_ease.iter().chain(&key.out_ease)).all(|ease| (ease.speed * factor).is_finite());
-                    (values_finite && speeds_finite).then_some(pose)
+                    let (rotation, factor) = uniform_rotation(m)?;
+                    let correction = if two_node {
+                        // A mirrored parent flips the aim, which this correction does not model.
+                        if factor <= 0.0 {
+                            return None;
+                        }
+                        let (w, h) = (comp.width as f64, comp.height as f64);
+                        let pos = ectx.v3(layer, tr, "position", [w / 2.0, h / 2.0, -1000.0]);
+                        let poi = ectx.v3(layer, tr, "poi", [w / 2.0, h / 2.0, 0.0]);
+                        aim_correction(rotation, [poi[0] - pos[0], poi[1] - pos[1], poi[2] - pos[2]])?
+                    } else {
+                        rotation
+                    };
+                    let orientation_finite = std::iter::once(&orientation.value)
+                        .chain(orientation.keys.iter().map(|key| &key.value))
+                        .all(|value| value.as_vec3().iter().all(|v| v.is_finite()));
+                    if !correction.0.iter().flatten().all(|v| v.is_finite()) || !orientation_finite {
+                        return None;
+                    }
+                    if let Some(scale) = scale {
+                        let values_finite = std::iter::once(&scale.value)
+                            .chain(scale.keys.iter().map(|key| &key.value))
+                            .all(|value| value.as_vec3().iter().all(|v| (v * factor).is_finite()));
+                        let speeds_finite = scale.keys.iter().all(|key| key.in_ease.iter().chain(&key.out_ease).all(|ease| (ease.speed * factor).is_finite()));
+                        if !values_finite || !speeds_finite {
+                            return None;
+                        }
+                    }
+                    Some(Pose3d { correction, factor })
                 });
                 fixes.push(ParentFix { layer: layer.id, m: effectcraft_geom::Mat3::IDENTITY, rotation: 0.0, scale: [1.0; 2], position_3d: Some(m), pose_3d });
             }

crates/engine/src/cmd/layer/transform.rs

@@ -74,14 +74,39 @@ pub(super) fn transform_op(s: &mut Session, p: &Value) -> Result<Value> {
     let op = str_p(p, "op").unwrap_or("reset").to_string();
     let comp = s.project.comp(cid).ok_or(EngineError::NoComp)?.clone();
     let t = s.time();
-    let sizes: Vec<(LayerId, (u32, u32))> =
-        comp.layers.iter().filter(|l| ids.contains(&l.id)).map(|l| (l.id, effectcraft_render::source_size(&s.project, l))).collect();
+    // A shape or text layer has no source item, so source_size is (0, 0): the fit ops size it by
+    // its painted bounds at the current time instead, and anchor at the bounds' centre — content
+    // bounds live in layer space, where a shape is centred on the origin and text sits above its
+    // baseline, so (w/2, h/2) would push it off-centre (#2198). Reset and the other ops keep the
+    // source size.
+    let ectx = effectcraft_render::EvalCtx {
+        expr: s.expr.as_deref(),
+        footage: Some(s.footage.as_ref()),
+        ..effectcraft_render::EvalCtx::new(&s.project, cid, &comp, t)
+    };
+    let fitting = matches!(op.as_str(), "fit" | "fitWidth" | "fitHeight");
+    let sizes: Vec<(LayerId, [f64; 2], [f64; 2])> = comp
+        .layers
+        .iter()
+        .filter(|l| ids.contains(&l.id))
+        .map(|l| {
+            let (w, h) = effectcraft_render::source_size(&s.project, l);
+            if fitting && (w == 0 || h == 0) {
+                match effectcraft_render::content_bounds(&ectx, l).filter(|b| b.iter().all(|v| v.is_finite()) && b[2] > b[0] && b[3] > b[1]) {
+                    Some(b) => (l.id, [b[2] - b[0], b[3] - b[1]], [(b[0] + b[2]) / 2.0, (b[1] + b[3]) / 2.0]),
+                    None => (l.id, [0.0; 2], [0.0; 2]),
+                }
+            } else {
+                (l.id, [w as f64, h as f64], [w as f64 / 2.0, h as f64 / 2.0])
+            }
+        })
+        .collect();
     s.edit("Transform", None, |proj, _| {
-        for (lid, (w, h)) in &sizes {
+        for (lid, size, anchor) in &sizes {
             let l = layer_mut(proj, cid, *lid)?;
             let lt = l.layer_time(t);
             let (cw, ch) = (comp.width as f64, comp.height as f64);
-            let (w, h) = (*w as f64, *h as f64);
+            let (w, h) = (size[0], size[1]);
             let Some(tr) = l.transform_mut() else { continue };
             let set = |tr: &mut PropGroup, m: &str, v: KV| {
                 if let Some(pr) = tr.get_mut(m) {
@@ -105,11 +130,15 @@ pub(super) fn transform_op(s: &mut Session, p: &Value) -> Result<Value> {
                         "fitHeight" => (ch / h, ch / h),
                         _ => (cw / w, ch / h),
                     };
+                    // A tiny shape's bounds can overflow the scale; refuse rather than write infinity.
+                    if !(sx * 100.0).is_finite() || !(sy * 100.0).is_finite() {
+                        return Err(EngineError::Other(format!("layer {} is too small to fit to the composition", lid.0)));
+                    }
                     let z = |m: &str, d: f64| tr.get(m).map(|p| p.value_at(lt).as_vec3()[2]).unwrap_or(d);
                     let (sz, az) = (z("scale", 100.0), z("anchor", 0.0));
                     set(tr, "scale", KV::Vec3([sx * 100.0, sy * 100.0, sz]));
                     update_position(tr, lt, |p| [cw / 2.0, ch / 2.0, p[2]]);
-                    set(tr, "anchor", KV::Vec3([w / 2.0, h / 2.0, az]));
+                    set(tr, "anchor", KV::Vec3([anchor[0], anchor[1], az]));
                 }
                 "flipH" | "flipV" => {
                     let cur = tr.get("scale").map(|p| p.value_at(lt).as_vec3()).unwrap_or([100.0; 3]);

crates/engine/src/cmd/layer_time.rs

@@ -185,7 +185,16 @@ fn freeze(s: &mut Session, p: &Value, last: bool) -> Result<Value> {
         return Err(bad("layer.freezeFrame", "freezing needs a footage or composition layer"));
     }
     // What each layer shows now (honouring an existing remap) — evaluated before the edit.
-    let ectx = effectcraft_render::EvalCtx { project: &s.project, comp_id: cid, comp, time: cti, expr: s.expr.as_deref(), footage: Some(s.footage.as_ref()) };
+    let ectx = effectcraft_render::EvalCtx {
+        project: &s.project,
+        comp_id: cid,
+        comp,
+        time: cti,
+        expr: s.expr.as_deref(),
+        footage: Some(s.footage.as_ref()),
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let now: Vec<(effectcraft_project::LayerId, f64)> = comp
         .layers
         .iter()

crates/engine/src/cmd/markers.rs

@@ -296,8 +296,9 @@ fn convert(s: &mut Session, p: &Value) -> Result<Value> {
     Ok(Value::Null)
 }
 
-/// Layer ▸ Markers ▸ Update Markers From Source: copy a precomp's composition markers onto the
-/// layer (layer time is the nested comp's time), skipping ones already there.
+/// Layer ▸ Markers ▸ Update Markers From Source: copy a precomp's composition markers, or the
+/// markers a footage file carries (a WAV's cue points), onto the layer (layer time is the source's
+/// time), skipping ones already there.
 fn update_from_source(s: &mut Session, p: &Value) -> Result<Value> {
     let (cid, ids) = layers_p(s, p)?;
     let src: Vec<(LayerId, Vec<Marker>)> = {
@@ -307,13 +308,17 @@ fn update_from_source(s: &mut Session, p: &Value) -> Result<Value> {
                 let l = comp.layer(*id)?;
                 match &l.source {
                     LayerSource::Comp { item } => Some((*id, s.project.comp(*item)?.markers.clone())),
+                    LayerSource::Footage { item } => match &s.project.item(*item)?.kind {
+                        effectcraft_project::ItemKind::Footage(f) => Some((*id, f.markers.clone())),
+                        _ => None,
+                    },
                     _ => None,
                 }
             })
             .collect()
     };
     if src.is_empty() {
-        return Err(bad("layer.updateMarkersFromSource", "select a precomposition layer"));
+        return Err(bad("layer.updateMarkersFromSource", "select a precomposition or footage layer"));
     }
     let n = s.edit("Update Markers From Source", None, |proj, _| {
         let c = proj.comp_mut(cid).ok_or(EngineError::NoComp)?;
@@ -323,8 +328,11 @@ fn update_from_source(s: &mut Session, p: &Value) -> Result<Value> {
             if l.markers_locked {
                 continue;
             }
+            // One set of the times already on the layer: a file with thousands of markers must not
+            // scan the layer's list for each of them.
+            let mut times: std::collections::HashSet<_> = l.markers.iter().map(|x| x.time).collect();
             for m in ms {
-                if !l.markers.iter().any(|x| x.time == m.time) {
+                if times.insert(m.time) {
                     l.markers.push(m.clone());
                     n += 1;
                 }
@@ -339,10 +347,10 @@ fn update_from_source(s: &mut Session, p: &Value) -> Result<Value> {
 fn has_precomp_layer(s: &Session) -> std::result::Result<(), String> {
     has_layers(s)?;
     let c = s.active_comp().ok_or("no composition")?;
-    if s.state.selected_layers.iter().filter_map(|l| c.layer(*l)).any(|l| matches!(l.source, LayerSource::Comp { .. })) {
+    if s.state.selected_layers.iter().filter_map(|l| c.layer(*l)).any(|l| matches!(l.source, LayerSource::Comp { .. } | LayerSource::Footage { .. })) {
         Ok(())
     } else {
-        Err("select a precomposition layer".into())
+        Err("select a precomposition or footage layer".into())
     }
 }
 

crates/engine/src/cmd/path_nulls.rs

@@ -78,7 +78,16 @@ fn info(s: &Session, cid: ItemId, lid: LayerId, uid: Uid, cmd: &str) -> Result<P
     let layer = comp.layer(lid).ok_or(EngineError::NoComp)?;
     let pr = layer.props.find(uid).ok_or_else(|| bad(cmd, "no such property"))?;
     let t = s.time();
-    let ctx = effectcraft_render::EvalCtx { project: &s.project, comp_id: cid, comp, time: t, expr: s.expr.as_deref(), footage: Some(s.footage.as_ref()) };
+    let ctx = effectcraft_render::EvalCtx {
+        project: &s.project,
+        comp_id: cid,
+        comp,
+        time: t,
+        expr: s.expr.as_deref(),
+        footage: Some(s.footage.as_ref()),
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let KV::Path(path) = ctx.value(layer, pr) else { return Err(bad(cmd, "that property is not a path")) };
     if path.vertices.is_empty() {
         return Err(bad(cmd, "the path has no vertices"));
@@ -147,8 +156,16 @@ fn pin_targets(s: &Session, p: &Value, cmd: &str) -> Result<Option<(ItemId, Vec<
     };
     let cid = pins.first().map(|x| x.0).ok_or_else(|| bad(cmd, "no puppet pins"))?;
     let comp = s.project.comp(cid).ok_or(EngineError::NoComp)?;
-    let ctx =
-        effectcraft_render::EvalCtx { project: &s.project, comp_id: cid, comp, time: s.time(), expr: s.expr.as_deref(), footage: Some(s.footage.as_ref()) };
+    let ctx = effectcraft_render::EvalCtx {
+        project: &s.project,
+        comp_id: cid,
+        comp,
+        time: s.time(),
+        expr: s.expr.as_deref(),
+        footage: Some(s.footage.as_ref()),
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let mut out = vec![];
     for (_, lid, uid) in pins {
         let Some(layer) = comp.layer(lid) else { continue };

crates/engine/src/cmd/prop.rs

@@ -1285,8 +1285,16 @@ fn convert_one_expr(s: &mut Session, cid: ItemId, lid: LayerId, uid: Uid) -> Res
     let fd = comp.frame_duration();
     let mut t = layer.in_point;
     while t < layer.out_point {
-        let ctx =
-            effectcraft_render::EvalCtx { project: &s.project, comp_id: cid, comp: &comp, time: t, expr: s.expr.as_deref(), footage: Some(s.footage.as_ref()) };
+        let ctx = effectcraft_render::EvalCtx {
+            project: &s.project,
+            comp_id: cid,
+            comp: &comp,
+            time: t,
+            expr: s.expr.as_deref(),
+            footage: Some(s.footage.as_ref()),
+            property_overrides: &[],
+            media_overrides: &[],
+        };
         keys.push(Keyframe::new(layer.layer_time(t), ctx.value(&layer, &pr)));
         t += fd;
     }

crates/engine/src/cmd/puppet.rs

@@ -38,7 +38,8 @@ pub fn puppet_eval(s: &Session, cid: ItemId, lid: LayerId, fx_uid: Uid, t: Tick)
     let fx = layer.effects()?;
     let index = fx.groups().position(|g| g.uid == fx_uid)?;
     let g = fx.groups().nth(index)?;
-    let ctx = EvalCtx { project: &s.project, comp_id: cid, comp, time: t, expr: s.expr.as_deref(), footage: None };
+    let ctx =
+        EvalCtx { project: &s.project, comp_id: cid, comp, time: t, expr: s.expr.as_deref(), footage: None, property_overrides: &[], media_overrides: &[] };
     let mut r = Renderer::new(&s.project, &*s.footage, RenderOpts::default());
     r.expr = s.expr.as_deref();
     r.cache = Some(&s.layer_cache);

crates/engine/src/cmd/render_queue.rs

@@ -619,7 +619,7 @@ fn set_output_module(s: &mut Session, p: &Value) -> Result<Value> {
         let (w, h) = item.settings.output_size(comp);
         let mut crop_only = om.clone();
         crop_only.resize.enabled = false;
-        let (cw, ch) = crop_only.frame_size(w, h, item.settings.resolution.clamp(0.01, 4.0));
+        let (cw, ch) = crop_only.frame_size(w, h, item.settings.effective_scale(comp));
         om.resize.width = ((om.resize.height as f64 * cw as f64 / ch as f64).round() as u32).clamp(1, 30_000);
     }
     let post = match str_p(p, "postRenderAction") {

crates/engine/src/cmd/rig3d.rs

@@ -48,7 +48,16 @@ impl Env {
         Env { time: s.time_of(cid), expr: s.expr.clone(), footage: s.footage.clone() }
     }
     fn ctx<'a>(&'a self, proj: &'a Project, cid: ItemId, comp: &'a Comp) -> EvalCtx<'a> {
-        EvalCtx { project: proj, comp_id: cid, comp, time: self.time, expr: self.expr.as_deref(), footage: Some(self.footage.as_ref()) }
+        EvalCtx {
+            project: proj,
+            comp_id: cid,
+            comp,
+            time: self.time,
+            expr: self.expr.as_deref(),
+            footage: Some(self.footage.as_ref()),
+            property_overrides: &[],
+            media_overrides: &[],
+        }
     }
 }
 

crates/engine/src/cmd/text_anim.rs

@@ -142,6 +142,7 @@ fn add_animator_prop(s: &mut Session, p: &Value) -> Result<Value> {
     }
     let layer = s.project.comp(cid).and_then(|c| c.layer(lid)).cloned().ok_or_else(|| bad(C, "no layer"))?;
     let auid = animator_uid(s, &layer, p, C)?;
+    let mut index = 0;
     s.edit("Add Text Animator Property", None, |proj, _| {
         let mut next = proj.next_id;
         let mut ids = Ids(&mut next);
@@ -151,10 +152,13 @@ fn add_animator_prop(s: &mut Session, p: &Value) -> Result<Value> {
         for k in &kinds {
             add_props(&mut ids, anim, k, three);
         }
+        // The requested property's 1-based position in the Properties group. A companion (such as
+        // Tracking Type) is added before it, so the first new child is not always the one asked for.
+        index = kinds.first().and_then(|k| anim.sub("properties")?.children.iter().position(|n| n.match_id() == k.as_str())).map_or(0, |i| i + 1);
         proj.next_id = next;
         Ok(())
     })?;
-    Ok(json!({"animator": auid}))
+    Ok(json!({"animator": auid, "index": index}))
 }
 
 pub(crate) fn add_selector(s: &mut Session, p: &Value) -> Result<Value> {

crates/engine/src/cmd/three_d.rs

@@ -413,7 +413,8 @@ fn get_3d(s: &mut Session, p: &Value) -> Result<Value> {
     let (w, h) = (comp.width as f64, comp.height as f64);
     let vs = s.state.views3d.get(&cid).cloned().unwrap_or_default();
     let t = s.state.times.get(&cid).copied().unwrap_or(Tick::ZERO);
-    let ctx = EvalCtx { project: &s.project, comp_id: cid, comp, time: t, expr: s.expr.as_deref(), footage: None };
+    let ctx =
+        EvalCtx { project: &s.project, comp_id: cid, comp, time: t, expr: s.expr.as_deref(), footage: None, property_overrides: &[], media_overrides: &[] };
     let cam = vs.override_camera(w, h).unwrap_or_else(|| camera::active_camera(&ctx));
     let f = cam.forward();
     let lights: Vec<Value> = comp
@@ -555,7 +556,8 @@ fn auto_orient(s: &mut Session, p: &Value) -> Result<Value> {
 /// through each layer's world matrix; cameras and lights contribute their position).
 fn layer_points(s: &Session, cid: ItemId, ids: &[LayerId], t: Tick) -> Vec<Vec3> {
     let Some(comp) = s.project.comp(cid) else { return vec![] };
-    let ctx = EvalCtx { project: &s.project, comp_id: cid, comp, time: t, expr: s.expr.as_deref(), footage: None };
+    let ctx =
+        EvalCtx { project: &s.project, comp_id: cid, comp, time: t, expr: s.expr.as_deref(), footage: None, property_overrides: &[], media_overrides: &[] };
     let mut out = vec![];
     for l in comp.layers.iter().filter(|l| ids.contains(&l.id)) {
         let m = ctx.world_matrix(l);

crates/engine/src/footage/footage_reload.rs

@@ -81,6 +81,8 @@ fn refreshed(s: &Session, f: &Footage, probed: Footage) -> Footage {
     nf.codec = probed.codec;
     nf.has_video = probed.has_video;
     nf.has_audio = probed.has_audio;
+    // The markers the file carries now (a WAV's cue points), for Update Markers From Source.
+    nf.markers = probed.markers;
     if matches!(f.kind, FootageKind::Video | FootageKind::Audio) {
         nf.duration = probed.duration;
         // Interpret Footage ▸ Conform to frame rate stays; the file's own rate is refreshed.

crates/engine/src/tests.rs

@@ -15,6 +15,7 @@ mod frame_export;
 mod fuzz_open;
 mod history;
 mod import_project;
+mod instance3d;
 mod key_metadata_order;
 mod key_time;
 mod keyframe_text;

crates/engine/src/tests/crypto_pick.rs

@@ -190,7 +190,16 @@ fn rendered_matte_of_pick(s: &mut Session, x: f64, y: f64, scale: f64) -> (Strin
     s.execute_checked("prop.set", json!({"path": format!("effects/#{fx}/matteOnly"), "value": true})).unwrap();
     let (cid, comp) = (s.active_comp_id().unwrap(), s.active_comp().unwrap());
     let layer = &comp.layers[0];
-    let ctx = effectcraft_render::EvalCtx { project: &s.project, comp_id: cid, comp, time: Tick::ZERO, expr: None, footage: None };
+    let ctx = effectcraft_render::EvalCtx {
+        project: &s.project,
+        comp_id: cid,
+        comp,
+        time: Tick::ZERO,
+        expr: None,
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let buf = s.renderer(effectcraft_render::RenderOpts { scale, ..Default::default() }).content_buf(&ctx, layer).unwrap();
     let (px, py) = buf.to_px([x, y]);
     let m = buf.img.get(px.floor() as i64, py.floor() as i64)[0];

crates/engine/src/tests/essential.rs

@@ -367,6 +367,128 @@ fn media_replacement_swaps_footage_per_instance() {
     assert!(center(&s, main)[0] > 0.99);
 }
 
+/// #1747: a collapsed precomp with an Essential Property override must keep drawing its nested
+/// layers past the precomp's frame instead of falling back to a flattened, clipped frame.
+#[test]
+fn collapsed_precomp_applies_property_overrides_without_clipping() {
+    struct AddY;
+    impl effectcraft_render::ExprHost for AddY {
+        fn eval(
+            &self,
+            _: &effectcraft_render::EvalCtx,
+            _: &effectcraft_project::Layer,
+            _: &effectcraft_project::Property,
+            value: &effectcraft_keyframe::Value,
+        ) -> Result<effectcraft_keyframe::Value, String> {
+            Ok(match value {
+                effectcraft_keyframe::Value::Vec3([x, y, z]) => effectcraft_keyframe::Value::Vec3([*x, y + 100.0, *z]),
+                _ => value.clone(),
+            })
+        }
+    }
+    let mut s = Session::default();
+    s.execute("comp.new", json!({"name": "Inner", "width": 400, "height": 300, "frameRate": 30, "duration": 2})).unwrap();
+    let inner = s.active_comp_id().unwrap();
+    let box_ = s.execute("layer.newSolid", json!({"name": "Box", "color": "#ffffff", "width": 100, "height": 100})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("prop.set", json!({"layer": box_, "path": "transform/position", "value": [200, 50, 0]})).unwrap();
+    // The source property's expression still runs after the instance override.
+    s.execute("prop.setExpression", json!({"layer": box_, "path": "transform/position", "expression": "value + [0, 100, 0]"})).unwrap();
+    let position = s.execute("essential.addProperty", json!({"layer": box_, "path": "transform/position"})).unwrap()["controls"][0].as_u64().unwrap();
+    s.execute("comp.new", json!({"name": "Outer", "width": 400, "height": 600, "frameRate": 30, "duration": 2})).unwrap();
+    let outer = s.active_comp_id().unwrap();
+    let instance = s.execute("layer.addItem", json!({"item": inner.0})).unwrap()["layer"].as_u64().unwrap();
+    let other = s.execute("layer.addItem", json!({"item": inner.0})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("layer.setSwitch", json!({"layers": [instance, other], "switch": "collapse", "value": true})).unwrap();
+    s.expr = Some(std::sync::Arc::new(AddY));
+    s.execute("layer.select", json!({"layers": [instance]})).unwrap();
+    s.execute("essential.set", json!({"layer": instance, "control": position, "value": [200, -120, 0]})).unwrap();
+    s.execute("layer.select", json!({"layers": [other]})).unwrap();
+    s.execute("essential.set", json!({"layer": other, "control": position, "value": [200, 220, 0]})).unwrap();
+    let img = s.render(outer, Tick::ZERO, RenderOpts::default());
+    // The expression adds 100 px: the overrides give inner y = -20 and 320. The first maps to
+    // outer y = 130 (the precomp is centred at 300) and its 100 px box spans 80..179, 70 px above
+    // the instance's frame (150..449), where a flattened precomp would stop. The second maps to
+    // 470 and spans 420..519, past the bottom.
+    assert!(img.get(200, 100)[3] > 0.99, "the override draws above the nested frame: {:?}", img.get(200, 100));
+    assert!(img.get(200, 90)[3] > 0.99, "the box reaches the top of its overridden bounds");
+    assert!(img.get(200, 500)[3] > 0.99, "the other instance keeps its own override: {:?}", img.get(200, 500));
+    assert!(img.get(200, 200)[3] < 0.01, "nothing is left between the instances");
+}
+
+/// #1747: two collapsed instances of the same comp keep their own source-affecting property
+/// overrides in the layer cache (the nested layers' ids and static values are identical).
+#[test]
+fn collapsed_instances_keep_distinct_property_overrides_in_the_cache() {
+    let mut s = Session::default();
+    s.execute("comp.new", json!({"name": "Card", "width": 64, "height": 64, "frameRate": 30, "duration": 2})).unwrap();
+    let card = s.active_comp_id().unwrap();
+    let solid = s.execute("layer.newSolid", json!({"name": "BG", "color": "#ffffff", "width": 64, "height": 64})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("effect.apply", json!({"layer": solid, "effect": "Fill"})).unwrap();
+    let color = s.execute("essential.addProperty", json!({"layer": solid, "path": "effects/#1/color"})).unwrap()["controls"][0].as_u64().unwrap();
+    s.execute("comp.new", json!({"name": "Main", "width": 200, "height": 100, "frameRate": 30, "duration": 2})).unwrap();
+    let main = s.active_comp_id().unwrap();
+    let a = s.execute("layer.addItem", json!({"item": card.0})).unwrap()["layer"].as_u64().unwrap();
+    let b = s.execute("layer.addItem", json!({"item": card.0})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("layer.setSwitch", json!({"layers": [a, b], "switch": "collapse", "value": true})).unwrap();
+    s.execute("prop.set", json!({"layer": a, "path": "transform/position", "value": [60, 50, 0]})).unwrap();
+    s.execute("prop.set", json!({"layer": b, "path": "transform/position", "value": [140, 50, 0]})).unwrap();
+    s.execute("layer.select", json!({"layers": [a]})).unwrap();
+    s.execute("essential.set", json!({"layer": a, "control": color, "value": [1.0, 0.0, 0.0, 1.0]})).unwrap();
+    s.execute("layer.select", json!({"layers": [b]})).unwrap();
+    s.execute("essential.set", json!({"layer": b, "control": color, "value": [0.0, 0.0, 1.0, 1.0]})).unwrap();
+    let img = s.render(main, Tick::ZERO, RenderOpts::default());
+    let left = img.get(60, 50);
+    let right = img.get(140, 50);
+    assert!(left[0] > 0.99 && left[2] < 0.01, "left instance is red: {left:?}");
+    assert!(right[2] > 0.99 && right[0] < 0.01, "right instance is blue: {right:?}");
+}
+
+/// #1747 with Media Replacement: the replacement footage and the position override both apply
+/// while the precomp stays collapsed, so the box is blue and still draws above the frame.
+#[test]
+fn collapsed_precomp_applies_media_replacement_without_clipping() {
+    struct Colors;
+    impl crate::render::FootageSource for Colors {
+        fn frame(&self, _: ItemId, f: &effectcraft_project::Footage, _: Tick) -> Option<std::sync::Arc<effectcraft_raster::Image>> {
+            let c = if f.path.contains("blue") { [0.0, 0.0, 1.0, 1.0] } else { [1.0, 0.0, 0.0, 1.0] };
+            Some(std::sync::Arc::new(effectcraft_raster::Image::filled(100, 100, c)))
+        }
+    }
+    let mut s = Session { footage: std::sync::Arc::new(Colors), ..Default::default() };
+    let footage = |path: &str| effectcraft_project::Footage {
+        path: path.into(),
+        kind: effectcraft_project::FootageKind::Still,
+        width: 100,
+        height: 100,
+        has_video: true,
+        ..Default::default()
+    };
+    let (red, blue) = s
+        .edit("test", None, |proj, _| {
+            let red = proj.add_item("red.png", Default::default(), None, effectcraft_project::ItemKind::Footage(footage("red.png")));
+            let blue = proj.add_item("blue.png", Default::default(), None, effectcraft_project::ItemKind::Footage(footage("blue.png")));
+            Ok((red, blue))
+        })
+        .unwrap();
+    s.execute("comp.new", json!({"name": "Inner", "width": 400, "height": 300, "frameRate": 30, "duration": 2})).unwrap();
+    let inner = s.active_comp_id().unwrap();
+    let clip = s.execute("layer.addItem", json!({"item": red.0})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("prop.set", json!({"layer": clip, "path": "transform/position", "value": [200, 50, 0]})).unwrap();
+    let media = s.execute("essential.addMedia", json!({"layer": clip})).unwrap()["control"].as_u64().unwrap();
+    let position = s.execute("essential.addProperty", json!({"layer": clip, "path": "transform/position"})).unwrap()["controls"][0].as_u64().unwrap();
+    s.execute("comp.new", json!({"name": "Outer", "width": 400, "height": 600, "frameRate": 30, "duration": 2})).unwrap();
+    let outer = s.active_comp_id().unwrap();
+    let instance = s.execute("layer.addItem", json!({"item": inner.0})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("layer.setSwitch", json!({"layers": [instance], "switch": "collapse", "value": true})).unwrap();
+    s.execute("layer.select", json!({"layers": [instance]})).unwrap();
+    s.execute("essential.set", json!({"layer": instance, "control": position, "value": [200, -20, 0]})).unwrap();
+    s.execute("essential.set", json!({"layer": instance, "control": media, "item": blue.0})).unwrap();
+    let img = s.render(outer, Tick::ZERO, RenderOpts::default());
+    let above = img.get(200, 100);
+    assert!(above[2] > 0.99 && above[0] < 0.01, "the replacement media is blue above the frame: {above:?}");
+    assert!(img.get(200, 200)[3] < 0.01, "the collapsed box is not clipped at the nested frame");
+}
+
 /// Responsive Design — Time: stretching a precomp keeps its protected regions at their
 /// original speed; the unprotected parts absorb the stretch.
 #[test]

crates/engine/src/tests/essential_more.rs

@@ -2,6 +2,7 @@
 
 use effectcraft_keyframe::Value as KV;
 use effectcraft_project::essential::{self, ControlType};
+use effectcraft_time::Tick;
 use serde_json::json;
 
 use crate::{Event, Session};
@@ -102,3 +103,33 @@ fn open_in_essential_graphics_sets_the_primary_comp() {
     );
     assert_eq!(s.execute("essential.list", json!({})).unwrap()["name"], "A");
 }
+
+/// #1747: through a collapsed precomp, a Text override and a Font override of the same Source
+/// Text both apply: the Font merges into the overridden text, as `essential::with_overrides`
+/// does on the flattened path, instead of one entry replacing the other.
+#[test]
+fn collapsed_instance_merges_text_and_font_overrides() {
+    let mut s = Session::default();
+    s.execute("comp.new", json!({"name": "Title", "width": 64, "height": 64, "frameRate": 30, "duration": 1})).unwrap();
+    let title = s.active_comp_id().unwrap();
+    let text = s.execute("layer.newText", json!({"text": "Hello"})).unwrap()["layer"].as_u64().unwrap();
+    let body = s.execute("essential.addProperty", json!({"layer": text, "path": "text/sourceText"})).unwrap()["controls"][0].as_u64().unwrap();
+    let font = s.execute("essential.addProperty", json!({"layer": text, "path": "text/sourceText", "as": "font"})).unwrap()["controls"][0].as_u64().unwrap();
+    s.execute("comp.new", json!({"name": "Main", "width": 64, "height": 64, "frameRate": 30, "duration": 1})).unwrap();
+    let main = s.active_comp_id().unwrap();
+    let inst = s.execute("layer.addItem", json!({"item": title.0})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("layer.setSwitch", json!({"layers": [inst], "switch": "collapse", "value": true})).unwrap();
+    s.execute("essential.set", json!({"layer": inst, "control": body, "value": "Bye"})).unwrap();
+    s.execute("essential.set", json!({"layer": inst, "control": font, "value": {"font": "Serif Test", "size": 40}})).unwrap();
+    // Evaluate the nested text in the collapsed instance's context, as the renderer does.
+    let r = effectcraft_render::Renderer::new(&s.project, &*s.footage, crate::render::RenderOpts::default());
+    let ctx = effectcraft_render::EvalCtx::new(&s.project, main, s.project.comp(main).unwrap(), Tick::ZERO);
+    let layer = ctx.comp.layer(effectcraft_project::LayerId(inst)).unwrap();
+    let collapsed = r.collapsed(&ctx, layer).expect("the instance collapses");
+    let (_, nctx) = r.collapse_into(&ctx, layer, &collapsed, 1.0).expect("a nested context");
+    let src = nctx.comp.layer(effectcraft_project::LayerId(text)).unwrap();
+    match nctx.value(src, src.props.prop("text/sourceText").unwrap()) {
+        KV::Text(d) => assert_eq!((d.text.as_str(), d.font.as_str(), d.size), ("Bye", "Serif Test", 40.0)),
+        o => panic!("{o:?}"),
+    }
+}

crates/engine/src/tests/instance3d.rs

@@ -0,0 +1,257 @@
+//! Create 3D Layer Instance (Layer ▸ Create): a comp-sized solid at the top of the layer stack
+//! with a 3D Layer Instance effect referencing the selected 3D model layer — a 2D copy of its
+//! render that 2D effects can be applied to (behaviour, pixels, undo/redo, serde).
+
+use std::sync::Arc;
+
+use effectcraft_keyframe::Value as KV;
+use effectcraft_project::{Footage, FootageKind, GroupKind, ItemId, Layer, LayerId, Project};
+use effectcraft_render::{FootageSource, RenderOpts};
+use effectcraft_time::{FrameRate, Tick};
+use serde_json::json;
+
+use crate::{Importer, Session};
+
+fn session() -> Session {
+    let mut s = Session { footage: Arc::new(DiskModels), importer: Some(Arc::new(ModelImporter)), ..Default::default() };
+    s.execute("comp.new", json!({"name": "Scene", "width": 640, "height": 360, "frameRate": 30, "duration": 2})).unwrap();
+    s
+}
+
+fn cid(s: &Session) -> ItemId {
+    s.active_comp_id().unwrap()
+}
+
+fn layer_in(s: &Session, comp: ItemId, id: u64) -> Layer {
+    s.project.comp(comp).unwrap().layer(LayerId(id)).unwrap().clone()
+}
+
+fn px(img: &effectcraft_raster::Image, x: u32, y: u32) -> [f32; 4] {
+    img.data[(y * img.width + x) as usize]
+}
+
+fn close(a: &effectcraft_raster::Image, b: &effectcraft_raster::Image, tol: f32) -> bool {
+    a.data.iter().zip(b.data.iter()).all(|(p, q)| p.iter().zip(q.iter()).all(|(x, y)| (x - y).abs() <= tol))
+}
+
+struct DiskModels;
+
+impl FootageSource for DiskModels {
+    fn frame(&self, _: ItemId, _: &Footage, _: Tick) -> Option<Arc<effectcraft_raster::Image>> {
+        None
+    }
+    fn model(&self, _: ItemId, f: &Footage) -> Option<Arc<effectcraft_model::Model>> {
+        let bytes = std::fs::read(&f.path).ok()?;
+        effectcraft_model::load(&f.path, &bytes, &|_| None).ok().map(Arc::new)
+    }
+}
+
+struct ModelImporter;
+
+impl Importer for ModelImporter {
+    fn probe(&self, path: &str) -> Result<Footage, String> {
+        effectcraft_model::format_of(path).ok_or("not a model")?;
+        Ok(Footage { path: path.into(), kind: FootageKind::Model, frame_rate: FrameRate::FPS_30, codec: "glTF".into(), ..Default::default() })
+    }
+}
+
+/// A red triangle in the Z = 0 plane (buffer embedded as a data URI).
+const TRIANGLE: &str = r#"{
+  "asset": {"version": "2.0"},
+  "scenes": [{"nodes": [0]}],
+  "nodes": [{"mesh": 0}],
+  "meshes": [{"primitives": [{"attributes": {"POSITION": 0, "NORMAL": 1}, "material": 0}]}],
+  "materials": [{"pbrMetallicRoughness": {"baseColorFactor": [1.0, 0.0, 0.0, 1.0]}}],
+  "buffers": [{"byteLength": 72, "uri": "data:application/octet-stream;base64,AACAvwAAgL8AAAAAAACAPwAAgL8AAAAAAAAAAAAAgD8AAAAAAAAAAAAAAAAAAIA/AAAAAAAAAAAAAIA/AAAAAAAAAAAAAIA/"}],
+  "bufferViews": [
+    {"buffer": 0, "byteOffset": 0, "byteLength": 36},
+    {"buffer": 0, "byteOffset": 36, "byteLength": 36}
+  ],
+  "accessors": [
+    {"bufferView": 0, "componentType": 5126, "type": "VEC3", "count": 3, "min": [-1.0, -1.0, 0.0], "max": [1.0, 1.0, 0.0]},
+    {"bufferView": 1, "componentType": 5126, "type": "VEC3", "count": 3}
+  ]
+}"#;
+
+fn triangle_model(s: &mut Session) -> u64 {
+    let dir = std::env::temp_dir().join(format!("ec-instance3d-{}", std::process::id()));
+    std::fs::create_dir_all(&dir).unwrap();
+    let path = dir.join("Triangle.gltf");
+    std::fs::write(&path, TRIANGLE).unwrap();
+    s.execute("layer.newModel", json!({"path": path.to_string_lossy(), "name": "Triangle"})).unwrap()["layer"].as_u64().unwrap()
+}
+
+#[test]
+fn instance3d_creates_a_2d_copy_of_the_model() {
+    let mut s = session();
+    let model = triangle_model(&mut s);
+    // The model renders through the comp's camera.
+    let before = s.render(cid(&s), Tick::ZERO, RenderOpts::default());
+    assert!(px(&before, 320, 180)[3] > 0.9, "the model covers the centre: {:?}", px(&before, 320, 180));
+    assert!(px(&before, 4, 4)[3] < 0.1, "the comp is transparent around it: {:?}", px(&before, 4, 4));
+    // Create 3D Layer Instance.
+    s.execute("layer.select", json!({"layers": [model]})).unwrap();
+    let r = s.execute("layer.create", json!({"op": "instance3d"})).unwrap();
+    let solid = r["layers"][0].as_u64().unwrap();
+    let comp = cid(&s);
+    let l = layer_in(&s, comp, solid);
+    assert_eq!(l.name, "Triangle Instance");
+    assert_eq!(s.active_comp().unwrap().layers[0].id.0, solid, "at the top of the layer stack");
+    // A 3D Layer Instance effect referencing the 3D layer.
+    let g = l.effects().unwrap().groups().next().unwrap().clone();
+    assert!(matches!(&g.kind, GroupKind::Effect { effect } if effect == "ec.3d.instance3d"), "{:?}", g.kind);
+    assert_eq!(g.get("layer").unwrap().value, KV::Layer(Some(model)));
+    // The model is switched off, the copy selected.
+    assert!(!layer_in(&s, comp, model).switches.video, "the referenced 3D layer is off, as After Effects does");
+    assert_eq!(s.state.selected_layers, vec![LayerId(solid)]);
+    // The comp renders the same through the copy: a 2D copy of the 3D layer, transparent
+    // around it.
+    let after = s.render(comp, Tick::ZERO, RenderOpts::default());
+    assert!(close(&before, &after, 2e-2), "the copy shows the model:\n{:?}\n{:?}", px(&before, 320, 180), px(&after, 320, 180));
+    assert!(px(&after, 320, 180)[3] > 0.9 && px(&after, 4, 4)[3] < 0.1, "{:?} {:?}", px(&after, 320, 180), px(&after, 4, 4));
+    // Undo removes the copy and switches the model back on; redo returns it.
+    s.execute("edit.undo", json!({})).unwrap();
+    assert!(s.active_comp().unwrap().layer(LayerId(solid)).is_none());
+    assert!(layer_in(&s, comp, model).switches.video);
+    s.execute("edit.redo", json!({})).unwrap();
+    assert!(s.active_comp().unwrap().layer(LayerId(solid)).is_some());
+    assert!(!layer_in(&s, comp, model).switches.video);
+    // Serde round-trips the layer parameter.
+    let j = serde_json::to_string(&*s.project).unwrap();
+    let back: Project = serde_json::from_str(&j).unwrap();
+    assert_eq!(back, *s.project);
+    // 2D effects can be applied to the copy (the model layer itself takes none): Fill in blue
+    // recolours the triangle.
+    s.execute("effect.apply", json!({"layer": solid, "effect": "ec.generate.fill"})).unwrap();
+    s.execute("prop.set", json!({"layer": solid, "path": "effects/#2/color", "value": [0.0, 0.0, 1.0, 1.0]})).unwrap();
+    let with_fx = s.render(comp, Tick::ZERO, RenderOpts::default());
+    let p = px(&with_fx, 320, 180);
+    assert!(p[2] > 0.9 && p[0] < 0.1, "the fill recolours the copy: {p:?}");
+}
+
+#[test]
+fn instance3d_also_takes_3d_primitives() {
+    let mut s = session();
+    let prim = s.execute("layer.new3dPrimitive", json!({"kind": "cube", "width": 200, "height": 200, "depth": 200})).unwrap()["layer"].as_u64().unwrap();
+    let before = s.render(cid(&s), Tick::ZERO, RenderOpts::default());
+    let r = s.execute("layer.create", json!({"op": "instance3d", "layers": [prim]})).unwrap();
+    let solid = r["layers"][0].as_u64().unwrap();
+    let l = layer_in(&s, cid(&s), solid);
+    assert_eq!(l.name, "Cube Instance");
+    assert!(!layer_in(&s, cid(&s), prim).switches.video);
+    let after = s.render(cid(&s), Tick::ZERO, RenderOpts::default());
+    assert!(close(&before, &after, 2e-2), "the copy shows the cube");
+}
+
+#[test]
+fn instance3d_needs_a_3d_layer() {
+    let mut s = session();
+    let solid = s.execute("layer.newSolid", json!({"color": "#808080", "width": 100, "height": 100})).unwrap()["layer"].as_u64().unwrap();
+    let err = s.execute_checked("layer.create", json!({"op": "instance3d", "layers": [solid]}));
+    assert!(err.is_err());
+    let text = s.execute("layer.newText", json!({"text": "hi"})).unwrap()["layer"].as_u64().unwrap();
+    assert!(s.execute_checked("layer.create", json!({"op": "instance3d", "layers": [text]})).is_err());
+    // A 3D-switched text layer is not a model layer either (it has 2D pixels of its own).
+    s.execute("layer.setSwitch", json!({"layers": [text], "switch": "threeD", "value": true})).unwrap();
+    assert!(s.execute_checked("layer.create", json!({"op": "instance3d", "layers": [text]})).is_err());
+}
+
+#[test]
+fn instance3d_creates_every_selected_copy_in_one_undo() {
+    let mut s = session();
+    let a = s.execute("layer.new3dPrimitive", json!({"kind": "cube", "width": 120, "height": 120, "depth": 120})).unwrap()["layer"].as_u64().unwrap();
+    let b = s.execute("layer.new3dPrimitive", json!({"kind": "cube", "width": 120, "height": 120, "depth": 120})).unwrap()["layer"].as_u64().unwrap();
+    let r = s.execute("layer.create", json!({"op": "instance3d", "layers": [a, b]})).unwrap();
+    let copies = r["layers"].as_array().unwrap();
+    assert_eq!(copies.len(), 2);
+    let (ia, ib) = (copies[0].as_u64().unwrap(), copies[1].as_u64().unwrap());
+    let comp = cid(&s);
+    assert_ne!(ia, ib);
+    assert_ne!(layer_in(&s, comp, ia).name, layer_in(&s, comp, ib).name, "each copy has a name of its own");
+    // Both sources are off, both copies selected, above their sources in the stack.
+    assert!(!layer_in(&s, comp, a).switches.video && !layer_in(&s, comp, b).switches.video);
+    let mut sel = s.state.selected_layers.clone();
+    let mut want = vec![LayerId(ia), LayerId(ib)];
+    sel.sort_by_key(|l| l.0);
+    want.sort_by_key(|l| l.0);
+    assert_eq!(sel, want);
+    let c = s.active_comp().unwrap();
+    let pos = |id: u64| c.layers.iter().position(|l| l.id.0 == id).unwrap();
+    assert!(pos(ia) < pos(a) && pos(ib) < pos(b), "the copies sit above their sources");
+    // One undo removes both copies and switches both models back on; one redo returns them.
+    s.execute("edit.undo", json!({})).unwrap();
+    let c = s.active_comp().unwrap();
+    assert!(c.layer(LayerId(ia)).is_none() && c.layer(LayerId(ib)).is_none(), "one undo removes every instance");
+    assert!(layer_in(&s, comp, a).switches.video && layer_in(&s, comp, b).switches.video);
+    s.execute("edit.redo", json!({})).unwrap();
+    let c = s.active_comp().unwrap();
+    assert!(c.layer(LayerId(ia)).is_some() && c.layer(LayerId(ib)).is_some(), "one redo returns every instance");
+    assert!(!layer_in(&s, comp, a).switches.video && !layer_in(&s, comp, b).switches.video);
+}
+
+#[test]
+fn instance3d_in_a_mixed_selection_only_takes_the_models() {
+    let mut s = session();
+    let model = triangle_model(&mut s);
+    let solid = s.execute("layer.newSolid", json!({"color": "#808080", "width": 100, "height": 100})).unwrap()["layer"].as_u64().unwrap();
+    let r = s.execute("layer.create", json!({"op": "instance3d", "layers": [model, solid]})).unwrap();
+    let copies = r["layers"].as_array().unwrap();
+    assert_eq!(copies.len(), 1, "only the model gets a copy: {r}");
+    let copy = copies[0].as_u64().unwrap();
+    let comp = cid(&s);
+    assert!(!layer_in(&s, comp, model).switches.video, "the model is switched off");
+    assert!(layer_in(&s, comp, solid).switches.video, "the plain solid is untouched");
+    let skipped = r["skipped"].as_array().unwrap();
+    assert_eq!(skipped.len(), 1);
+    assert!(skipped[0].as_str().unwrap().contains("not a 3D model layer"), "{skipped:?}");
+    // The copy references the model, not the solid.
+    let l = layer_in(&s, comp, copy);
+    let g = l.effects().unwrap().groups().next().unwrap().clone();
+    assert_eq!(g.get("layer").unwrap().value, KV::Layer(Some(model)));
+}
+
+#[test]
+fn instance3d_shows_nothing_outside_the_source_layer_range() {
+    let mut s = session();
+    let model = triangle_model(&mut s);
+    // The model's range ends at 1 s; the comp runs to 2 s.
+    let comp = cid(&s);
+    s.edit("trim", None, |p, _| {
+        p.comp_mut(comp).unwrap().layer_mut(LayerId(model)).unwrap().out_point = Tick::from_seconds_f64(1.0);
+        Ok(())
+    })
+    .unwrap();
+    s.execute("layer.select", json!({"layers": [model]})).unwrap();
+    let r = s.execute("layer.create", json!({"op": "instance3d"})).unwrap();
+    let _copy = r["layers"][0].as_u64().unwrap();
+    // Inside the model's range the copy shows it, transparent around it.
+    let inside = s.render(comp, Tick::from_seconds_f64(0.5), RenderOpts::default());
+    assert!(px(&inside, 320, 180)[3] > 0.9, "the copy shows the model: {:?}", px(&inside, 320, 180));
+    // After its out point the source has nothing to read: the copy is transparent.
+    let outside = s.render(comp, Tick::from_seconds_f64(1.5), RenderOpts::default());
+    assert!(outside.data.iter().all(|p| p[3] < 1e-3), "transparent after the source's out point: {:?}", px(&outside, 320, 180));
+}
+
+#[test]
+fn instance3d_keeps_the_copy_visible_when_the_source_is_soloed() {
+    let mut s = session();
+    let model = triangle_model(&mut s);
+    let comp = cid(&s);
+    // Solo the model, then create the instance: any_solo hides non-soloed layers and the
+    // source's video goes off, so the copy has to take the Solo over.
+    s.edit("solo", None, |p, _| {
+        p.comp_mut(comp).unwrap().layer_mut(LayerId(model)).unwrap().switches.solo = true;
+        Ok(())
+    })
+    .unwrap();
+    let before = s.render(comp, Tick::ZERO, RenderOpts::default());
+    assert!(px(&before, 320, 180)[3] > 0.9, "the soloed model shows: {:?}", px(&before, 320, 180));
+    s.execute("layer.select", json!({"layers": [model]})).unwrap();
+    let r = s.execute("layer.create", json!({"op": "instance3d"})).unwrap();
+    let solid = r["layers"][0].as_u64().unwrap();
+    assert!(layer_in(&s, comp, solid).switches.solo, "the copy takes the source's Solo switch");
+    assert!(!layer_in(&s, comp, model).switches.video, "the source keeps its video off");
+    let after = s.render(comp, Tick::ZERO, RenderOpts::default());
+    assert!(px(&after, 320, 180)[3] > 0.9, "the soloed copy shows the model: {:?}", px(&after, 320, 180));
+    assert!(close(&before, &after, 2e-2), "the comp renders the same through the copy:\n{:?}\n{:?}", px(&before, 320, 180), px(&after, 320, 180));
+}

crates/engine/src/tests/menu_cmds.rs

@@ -1103,6 +1103,66 @@ fn transform_commands_keep_depth_and_follow_separated_dimensions() {
     assert_eq!(pos(&s, b)[..2], [200.0, 100.0], "the 200×100 solid's centre");
 }
 
+/// The layer's painted bounds mapped to comp space — what the viewer shows.
+fn seen_bounds(s: &Session, lid: u64) -> [f64; 4] {
+    let cid = s.active_comp_id().unwrap();
+    let comp = s.project.comp(cid).unwrap().clone();
+    let layer = comp.layer(effectcraft_project::LayerId(lid)).unwrap();
+    let ectx = effectcraft_render::EvalCtx::new(&s.project, cid, &comp, s.time());
+    let b = effectcraft_render::content_bounds(&ectx, layer).expect("painted bounds");
+    let m = ectx.layer_to_comp(layer).0;
+    let corners = [[b[0], b[1]], [b[2], b[1]], [b[2], b[3]], [b[0], b[3]]];
+    let pts: Vec<[f64; 2]> = corners
+        .iter()
+        .map(|p| {
+            let q = m.apply(effectcraft_geom::vec2(p[0], p[1]));
+            [q.x, q.y]
+        })
+        .collect();
+    let (mut x0, mut y0, mut x1, mut y1) = (f64::INFINITY, f64::INFINITY, f64::NEG_INFINITY, f64::NEG_INFINITY);
+    for p in &pts {
+        x0 = x0.min(p[0]);
+        y0 = y0.min(p[1]);
+        x1 = x1.max(p[0]);
+        y1 = y1.max(p[1]);
+    }
+    [x0, y0, x1, y1]
+}
+
+#[test]
+fn fit_to_comp_fills_the_comp_with_shape_and_text_bounds() {
+    let mut s = comp();
+    let close = |x: f64, y: f64| (x - y).abs() < 1e-6;
+    // A shape or text layer has no source item: fit sizes it by its painted bounds, anchored at
+    // the bounds' centre, so what the viewer shows fills the frame (#2198).
+    let a = s.execute("layer.newShape", json!({"kind": "rect", "size": [180, 80]})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("layer.transform", json!({"layers": [a], "op": "fit"})).unwrap();
+    let seen = seen_bounds(&s, a);
+    assert!(close(seen[0], 0.0) && close(seen[1], 0.0) && close(seen[2], 640.0) && close(seen[3], 360.0), "the rect's painted bounds fill the comp: {seen:?}");
+
+    let t = s.execute("layer.newText", json!({"text": "Title", "size": 80})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("layer.transform", json!({"layers": [t], "op": "fit"})).unwrap();
+    let seen = seen_bounds(&s, t);
+    assert!(close(seen[0], 0.0) && close(seen[1], 0.0) && close(seen[2], 640.0) && close(seen[3], 360.0), "the text's painted bounds fill the comp: {seen:?}");
+
+    // fitWidth spans the comp's width and centres vertically.
+    for lid in [a, t] {
+        s.execute("layer.transform", json!({"layers": [lid], "op": "fitWidth"})).unwrap();
+        let seen = seen_bounds(&s, lid);
+        assert!(close(seen[0], 0.0) && close(seen[2], 640.0), "fitWidth spans the comp width: {seen:?}");
+        assert!(close((seen[1] + seen[3]) / 2.0, 180.0), "fitWidth centres vertically: {seen:?}");
+    }
+}
+
+#[test]
+fn fit_to_comp_refuses_a_scale_that_overflows() {
+    let mut s = comp();
+    let a = s.execute("layer.newShape", json!({"kind": "rect", "size": [1e-305, 80]})).unwrap()["layer"].as_u64().unwrap();
+    let before = s.project.clone();
+    assert!(s.execute("layer.transform", json!({"layers": [a], "op": "fit"})).is_err(), "an infinite scale is refused");
+    assert_eq!(s.project, before, "nothing was written");
+}
+
 #[test]
 fn duplicated_and_pasted_layers_keep_their_links() {
     let mut s = comp();

crates/engine/src/tests/rig3d.rs

@@ -7,7 +7,7 @@ use std::sync::Arc;
 use effectcraft_geom::{Vec3, vec3};
 use effectcraft_keyframe::Value as KV;
 use effectcraft_project::{Footage, FootageKind, GroupKind, ItemId, Layer, LayerId, LayerSource, LightKind, Project};
-use effectcraft_render::three_d::camera::layer_frame;
+use effectcraft_render::three_d::camera::{is_two_node, layer_frame};
 use effectcraft_render::{EvalCtx, FootageSource, RenderOpts};
 use effectcraft_time::{FrameRate, Tick};
 use serde_json::{Value, json};
@@ -40,7 +40,7 @@ fn close3(a: [f64; 3], b: [f64; 3], tol: f64) -> bool {
 fn frame(s: &Session, id: u64) -> (Vec3, Vec3) {
     let c = cid(s);
     let comp = s.project.comp(c).unwrap();
-    let ctx = EvalCtx { project: &s.project, comp_id: c, comp, time: Tick::ZERO, expr: None, footage: None };
+    let ctx = EvalCtx { project: &s.project, comp_id: c, comp, time: Tick::ZERO, expr: None, footage: None, property_overrides: &[], media_overrides: &[] };
     let (e, f, _) = layer_frame(&ctx, comp.layer(LayerId(id)).unwrap());
     (e, f)
 }
@@ -217,8 +217,189 @@ fn control_light_with_camera_follows_and_releases() {
     assert!(s.execute("light.controlWithCamera", json!({"layers": [cam]})).is_err());
 }
 
+/// Parenting keeps a camera where it is (After Effects' Parent & Link): Position and Point of
+/// Interest are re-expressed in the null's space, so the frame does not move.
+#[test]
+fn parented_camera_keeps_its_frame_under_an_offset_null() {
+    let mut s = session();
+    let cam = camera(&mut s);
+    let (eye0, f0) = frame(&s, cam);
+    let nul = s.execute("layer.newNull", json!({})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("prop.set", json!({"layer": nul, "path": "transform/position", "value": [100, 60, 0]})).unwrap();
+    s.execute("layer.setParent", json!({"layers": [cam], "parent": nul})).unwrap();
+    let (eye1, f1) = frame(&s, cam);
+    assert!((eye1 - eye0).length() < 1e-6 && (f1 - f0).length() < 1e-6, "{eye0:?} {eye1:?}");
+    // The null's origin is Position minus its default anchor (50, 50): (50, 10) in the comp.
+    let c = layer_in(&s, cid(&s), cam);
+    assert!(close3(v3(&c, "transform/position"), [270.0, 170.0, -800.0], 1e-6), "{:?}", v3(&c, "transform/position"));
+    assert!(close3(v3(&c, "transform/poi"), [270.0, 170.0, 0.0], 1e-6), "{:?}", v3(&c, "transform/poi"));
+    // Moving the null carries the camera and keeps its aim.
+    s.execute("prop.set", json!({"layer": nul, "path": "transform/position", "value": [140, 90, 0]})).unwrap();
+    let (eye2, f2) = frame(&s, cam);
+    assert!((eye2 - (eye0 + vec3(40.0, 30.0, 0.0))).length() < 1e-6, "{eye2:?}");
+    assert!((f2 - f0).length() < 1e-6, "{f2:?}");
+}
+
+/// World (eye, forward, down) of a layer in the active comp at time `t`.
+fn frame_at(s: &Session, id: u64, t: Tick) -> (Vec3, Vec3, Vec3) {
+    let c = cid(s);
+    let comp = s.project.comp(c).unwrap();
+    let ctx = EvalCtx { project: &s.project, comp_id: c, comp, time: t, expr: None, footage: None, property_overrides: &[], media_overrides: &[] };
+    layer_frame(&ctx, comp.layer(LayerId(id)).unwrap())
+}
+
+/// Whether two frames agree on eye, forward and down.
+fn frames_match(a: (Vec3, Vec3, Vec3), b: (Vec3, Vec3, Vec3)) -> bool {
+    (a.0 - b.0).length() < 1e-6 && (a.1 - b.1).length() < 1e-6 && (a.2 - b.2).length() < 1e-6
+}
+
+/// A 3D null off-centre in the comp, with an Orientation and a Z rotation.
+fn rotated_null(s: &mut Session, orientation: [f64; 3], turn: f64) -> u64 {
+    let nul = s.execute("layer.newNull", json!({})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("layer.setSwitch", json!({"layers": [nul], "switch": "threeD", "value": true})).unwrap();
+    s.execute("prop.set", json!({"layer": nul, "path": "transform/position", "value": [100, 60, 40]})).unwrap();
+    s.execute("prop.set", json!({"layer": nul, "path": "transform/orientation", "value": orientation})).unwrap();
+    s.execute("prop.set", json!({"layer": nul, "path": "transform/rotation", "value": turn})).unwrap();
+    nul
+}
+
+/// A two-node camera under a rotated null keeps its eye, aim and roll: its Orientation is
+/// re-expressed against the new aim, so Up does not drift.
+#[test]
+fn two_node_camera_under_rotated_null_keeps_its_roll() {
+    let mut s = session();
+    let cam = camera(&mut s);
+    s.execute("prop.set", json!({"layer": cam, "path": "transform/rotation", "value": 25})).unwrap();
+    assert!(is_two_node(&layer_in(&s, cid(&s), cam)));
+    let before = frame_at(&s, cam, Tick::ZERO);
+    let nul = rotated_null(&mut s, [20.0, -35.0, 60.0], 30.0);
+    s.execute("layer.setParent", json!({"layers": [cam], "parent": nul})).unwrap();
+    let after = frame_at(&s, cam, Tick::ZERO);
+    assert!(frames_match(before, after), "{before:?} {after:?}");
+}
+
+#[test]
+fn parented_point_light_keeps_its_direction_under_a_rotated_null() {
+    let mut s = session();
+    let light = s.execute("layer.newLight", json!({"kind": "Point", "position": [320, 180, -500]})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("prop.set", json!({"layer": light, "path": "transform/orientation", "value": [30, 0, 0]})).unwrap();
+    let (eye0, f0) = frame(&s, light);
+    let nul = s.execute("layer.newNull", json!({})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("prop.set", json!({"layer": nul, "path": "transform/position", "value": [100, 60, 0]})).unwrap();
+    s.execute("prop.set", json!({"layer": nul, "path": "transform/rotation", "value": 30})).unwrap();
+    s.execute("layer.setParent", json!({"layers": [light], "parent": nul})).unwrap();
+    let (eye1, f1) = frame(&s, light);
+    assert!((eye1 - eye0).length() < 1e-6 && (f1 - f0).length() < 1e-6, "{eye0:?} {eye1:?} {f0:?} {f1:?}");
+}
+
+/// Keyed Orientation under a Z-only turn is shifted exactly, so the light keeps its direction at
+/// every time, between the keys too.
+#[test]
+fn keyed_orientation_under_a_z_turn_keeps_the_direction_at_every_time() {
+    let mut s = session();
+    let light = s.execute("layer.newLight", json!({"kind": "Point", "position": [320, 180, -500]})).unwrap()["layer"].as_u64().unwrap();
+    for (time, value) in [(0.0, json!([-8.0, 12.0, -13.0])), (1.0, json!([5.0, 18.0, 14.0]))] {
+        s.execute("prop.addKey", json!({"layer": light, "path": "transform/orientation", "time": time, "value": value})).unwrap();
+    }
+    let times = [0.0, 0.25, 0.5, 0.75, 1.0].map(Tick::from_seconds_f64);
+    let before = times.map(|t| frame_at(&s, light, t));
+    let nul = rotated_null(&mut s, [0.0, 0.0, 0.0], 30.0);
+    s.execute("layer.setParent", json!({"layers": [light], "parent": nul})).unwrap();
+    for (t, b) in times.into_iter().zip(before) {
+        assert!(frames_match(b, frame_at(&s, light, t)), "a Z-only turn keeps the light's direction");
+    }
+}
+
+/// Under a tilted null the keys alone cannot follow (Euler angles are blended between them), so keys are
+/// added between them: the light keeps its direction within a small angle at every time.
+#[test]
+fn keyed_orientation_under_a_tilted_null_follows_between_the_keys() {
+    {
+        let mut s = session();
+        let light = s.execute("layer.newLight", json!({"kind": "Point", "position": [320, 180, -500]})).unwrap()["layer"].as_u64().unwrap();
+        for (time, value) in [(0.0, json!([-8.0, 12.0, -13.0])), (1.5, json!([50.0, 118.0, 74.0]))] {
+            s.execute("prop.addKey", json!({"layer": light, "path": "transform/orientation", "time": time, "value": value})).unwrap();
+        }
+        let times = [0.0, 0.2, 0.5, 0.9, 1.3, 1.5].map(Tick::from_seconds_f64);
+        let before = times.map(|t| frame_at(&s, light, t));
+        let nul = rotated_null(&mut s, [20.0, -35.0, 60.0], 30.0);
+        s.execute("layer.setParent", json!({"layers": [light], "parent": nul})).unwrap();
+        for (t, b) in times.into_iter().zip(before) {
+            let a = frame_at(&s, light, t);
+            // 0.05 degrees is about 9e-4 of a radian on a unit vector.
+            assert!((a.0 - b.0).length() < 1e-6 && (a.1 - b.1).length() < 2e-3, "at {t:?}: {:?} vs {:?}", a.1, b.1);
+        }
+        assert!(layer_in(&s, cid(&s), light).props.prop("transform/orientation").unwrap().keys.len() > 2, "keys were added between the two");
+    }
+}
+
+/// A one-node light parented under a mirrored null (Z scale -100%) keeps the Position and
+/// Orientation it was authored with: it has no Scale to carry the mirror, so none of it is
+/// compensated rather than reversing its frame (a half-compensated light would point backwards).
+#[test]
+fn one_node_light_under_a_mirrored_null_keeps_its_authored_values() {
+    let mut s = session();
+    let light = s.execute("layer.newLight", json!({"kind": "Point", "position": [320, 180, -500]})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("prop.set", json!({"layer": light, "path": "transform/orientation", "value": [30, 0, 0]})).unwrap();
+    let before = layer_in(&s, cid(&s), light);
+    let nul = rotated_null(&mut s, [0.0, 0.0, 0.0], 0.0);
+    s.execute("prop.set", json!({"layer": nul, "path": "transform/scale", "value": [100, 100, -100]})).unwrap();
+    s.execute("layer.setParent", json!({"layers": [light], "parent": nul})).unwrap();
+    let after = layer_in(&s, cid(&s), light);
+    assert_eq!(after.parent, Some(LayerId(nul)));
+    assert_eq!(v3(&after, "transform/position"), v3(&before, "transform/position"));
+    assert_eq!(v3(&after, "transform/orientation"), v3(&before, "transform/orientation"));
+}
+
+/// The cap on keys added by baking is for the whole Orientation property, not for each segment:
+/// many strongly eased segments under a tilted parent stay within it.
+#[test]
+fn baked_orientation_keys_are_capped_across_the_whole_property() {
+    let mut s = session();
+    let light = s.execute("layer.newLight", json!({"kind": "Point", "position": [320, 180, -500]})).unwrap()["layer"].as_u64().unwrap();
+    let count = 120;
+    for i in 0..count {
+        let swing = if i % 2 == 0 { json!([0.0, 0.0, 0.0]) } else { json!([170.0, 60.0, 120.0]) };
+        s.execute("prop.addKey", json!({"layer": light, "path": "transform/orientation", "time": i as f64 * 0.05, "value": swing})).unwrap();
+    }
+    let uid = layer_in(&s, cid(&s), light).props.prop("transform/orientation").unwrap().uid;
+    let keys: Vec<_> = (0..count).map(|i| json!({"layer": light, "prop": uid, "time": i as f64 * 0.05})).collect();
+    s.execute("keys.select", json!({"keys": keys})).unwrap();
+    s.execute("keys.easyEase", json!({})).unwrap();
+    let nul = rotated_null(&mut s, [20.0, -35.0, 60.0], 30.0);
+    s.execute("layer.setParent", json!({"layers": [light], "parent": nul})).unwrap();
+    let n = layer_in(&s, cid(&s), light).props.prop("transform/orientation").unwrap().keys.len();
+    assert!(n <= 4096, "{n} keys: the cap is for the property, not per segment");
+    // the segments the cap left unchecked keep their authored easing instead of turning into straight blends
+    let orientation = layer_in(&s, cid(&s), light);
+    let keys = &orientation.props.prop("transform/orientation").unwrap().keys;
+    let last = keys.iter().rev().nth(1).expect("the penultimate key");
+    assert_ne!(last.out_interp, effectcraft_keyframe::Interp::Linear, "the last segment keeps its authored easing");
+}
+
 // ---------------------------------------------------------------- from 3D model
 
+/// Easy Ease agrees with a straight blend at the midpoint, but not at the quarter points.
+#[test]
+fn eased_orientation_under_x_parent_keeps_motion_between_keys() {
+    let mut s = session();
+    let light = s.execute("layer.newLight", json!({"kind": "Point", "position": [320, 180, -500]})).unwrap()["layer"].as_u64().unwrap();
+    for (time, value) in [(0.0, json!([0.0, 0.0, 0.0])), (1.0, json!([90.0, 0.0, 0.0]))] {
+        s.execute("prop.addKey", json!({"layer": light, "path": "transform/orientation", "time": time, "value": value})).unwrap();
+    }
+    let uid = layer_in(&s, cid(&s), light).props.prop("transform/orientation").unwrap().uid;
+    s.execute("keys.select", json!({"keys": [{"layer": light, "prop": uid, "time": 0.0}, {"layer": light, "prop": uid, "time": 1.0}]})).unwrap();
+    s.execute("keys.easyEase", json!({})).unwrap();
+    let times: Vec<_> = (0..=100).map(|i| Tick::from_seconds_f64(i as f64 / 100.0)).collect();
+    let before: Vec<_> = times.iter().map(|t| frame_at(&s, light, *t)).collect();
+    let parent = rotated_null(&mut s, [30.0, 0.0, 0.0], 0.0);
+    s.execute("layer.setParent", json!({"layers": [light], "parent": parent})).unwrap();
+    for (t, b) in times.into_iter().zip(before) {
+        let a = frame_at(&s, light, t);
+        assert!((a.0 - b.0).length() < 1e-6 && (a.1 - b.1).length() < 1e-3, "at {t:?}: {:?} vs {:?}", a.1, b.1);
+    }
+}
+
 struct DiskModels;
 
 impl FootageSource for DiskModels {

crates/engine/src/tests/sequence.rs

@@ -182,14 +182,58 @@ fn interpret_footage_start_timecode_relabels_source_time() {
 }
 
 #[test]
-fn replace_footage_and_reload_keep_sequences() {
+fn replace_footage_keeps_a_still_a_still() {
     let dir = folder(&RUN);
     let mut s = session();
     let item = s.execute("file.import", json!({"paths": [at(&dir, "shot_0001.png")], "sequence": false})).unwrap()["items"][0].clone();
     s.state.project_selection = vec![ItemId(item.as_u64().unwrap())];
+    // Replacing with a numbered still does not silently turn the item into a sequence (#2073).
     s.execute("file.replaceFootage", json!({"path": at(&dir, "shot_0004.png")})).unwrap();
     let (name, f) = footage(&s, &item);
-    assert_eq!((name.as_str(), f.sequence.len()), ("shot_[0001-0005].png", 4));
+    assert_eq!((name.as_str(), f.kind), ("shot_0004.png", FootageKind::Still));
+    // JSON null is unspecified, not "on": the still stays a still.
+    s.execute("file.replaceFootage", json!({"path": at(&dir, "shot_0004.png"), "sequence": null})).unwrap();
+    let (name, f) = footage(&s, &item);
+    assert_eq!((name.as_str(), f.kind), ("shot_0004.png", FootageKind::Still));
+    // Alphabetical is a sequence modifier, not a request to make one.
+    s.execute("file.replaceFootage", json!({"path": at(&dir, "shot_0004.png"), "alphabetical": true})).unwrap();
+    let (name, f) = footage(&s, &item);
+    assert_eq!((name.as_str(), f.kind), ("shot_0004.png", FootageKind::Still));
+    // Asking for the run still brings it.
+    s.execute("file.replaceFootage", json!({"path": at(&dir, "shot_0004.png"), "sequence": true})).unwrap();
+    let (name, f) = footage(&s, &item);
+    assert_eq!((name.as_str(), f.kind, f.sequence.len()), ("shot_[0001-0005].png", FootageKind::Sequence, 4));
+}
+
+#[test]
+fn replace_footage_keeps_a_one_frame_run_a_sequence() {
+    let dir = folder(&["shot_0001.png", "shot_0002.png", "solo_0007.png", "cover.png"]);
+    let mut s = session();
+    let item = s.execute("file.import", json!({"paths": [at(&dir, "shot_0001.png")], "sequence": true})).unwrap()["items"][0].clone();
+    s.state.project_selection = vec![ItemId(item.as_u64().unwrap())];
+    // A numbered file with no other frame in its run is still the replacement for a sequence.
+    s.execute("file.replaceFootage", json!({"path": at(&dir, "solo_0007.png")})).unwrap();
+    let (name, f) = footage(&s, &item);
+    assert_eq!((name.as_str(), f.kind, f.sequence.len()), ("solo_0007.png", FootageKind::Sequence, 1));
+    // A single-file source keeps the sequence kind too.
+    s.execute("file.replaceFootage", json!({"path": at(&dir, "cover.png")})).unwrap();
+    let (name, f) = footage(&s, &item);
+    assert_eq!((name.as_str(), f.kind, f.sequence.len()), ("cover.png", FootageKind::Sequence, 1));
+    // An explicit `sequence: false` still asks for one frame.
+    s.execute("file.replaceFootage", json!({"path": at(&dir, "cover.png"), "sequence": false})).unwrap();
+    let (_, f) = footage(&s, &item);
+    assert_eq!((f.kind, f.sequence.len()), (FootageKind::Still, 0));
+}
+
+#[test]
+fn replace_footage_and_reload_keep_sequences() {
+    let dir = folder(&RUN);
+    let mut s = session();
+    let item = s.execute("file.import", json!({"paths": [at(&dir, "shot_0001.png")], "sequence": true})).unwrap()["items"][0].clone();
+    s.state.project_selection = vec![ItemId(item.as_u64().unwrap())];
+    s.execute("file.replaceFootage", json!({"path": at(&dir, "shot_0004.png")})).unwrap();
+    let (name, f) = footage(&s, &item);
+    assert_eq!((name.as_str(), f.kind, f.sequence.len()), ("shot_[0001-0005].png", FootageKind::Sequence, 4));
     // Reload finds a new frame and keeps the interpretation.
     s.execute("file.interpretFootage", json!({"items": [item], "frameRate": 12, "startTimecode": 2})).unwrap();
     std::fs::write(at(&dir, "shot_0003.png"), b"").unwrap();

crates/engine/src/tests/tail.rs

@@ -421,6 +421,70 @@ fn camera_focus_commands_undo_and_serde() {
     assert!(s.execute("camera.linkFocusToPoi", json!({})).is_ok());
 }
 
+/// Set Focus Distance to Layer: degenerate targets (behind the camera, exactly at it) are clean
+/// errors, and a depth-of-field frame renders right after the command.
+#[test]
+fn camera_set_focus_to_layer_degenerate_targets_and_dof_frame() {
+    let mut s = comp(400, 300);
+    let t = s.execute("layer.newSolid", json!({"color": "#ffffff", "width": 50, "height": 50})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("layer.setSwitch", json!({"layers": [t], "switch": "threeD", "value": true})).unwrap();
+    let cam = s.execute("layer.newCamera", json!({})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("prop.set", json!({"layer": cam, "path": "transform/position", "value": [200, 150, -500]})).unwrap();
+    s.execute("prop.set", json!({"layer": cam, "path": "cameraOptions/dof", "value": true})).unwrap();
+    s.execute("layer.select", json!({"layers": [cam, t]})).unwrap();
+    // Behind the camera (which now sits at z = −500 looking towards +z).
+    s.execute("layer.setTransform", json!({"layer": t, "prop": "position", "value": [200, 150, -1000]})).unwrap();
+    let e = s.execute("camera.setFocusToLayer", json!({})).unwrap_err().to_string();
+    assert!(e.contains("behind the camera"), "{e}");
+    // Exactly at the camera: depth 0, still a clean error.
+    s.execute("layer.setTransform", json!({"layer": t, "prop": "position", "value": [200, 150, -500]})).unwrap();
+    assert!(s.execute("camera.setFocusToLayer", json!({})).is_err());
+    // In front: the command works, and the depth-of-field frame renders with finite pixels.
+    s.execute("layer.setTransform", json!({"layer": t, "prop": "position", "value": [200, 150, 400]})).unwrap();
+    let d = s.execute("camera.setFocusToLayer", json!({})).unwrap()["focusDistance"].as_f64().unwrap();
+    assert!((d - 900.0).abs() < 1e-6, "{d}");
+    // An out-of-focus 3D layer, which must visibly blur, and a 0%-scaled one, whose pixels cover
+    // ~0 screen pixels and so turn an ordinary defocus into a radius of ~1e9 buffer pixels.
+    s.execute("prop.set", json!({"layer": cam, "path": "cameraOptions/aperture", "value": 120})).unwrap();
+    let blur = s.execute("layer.newSolid", json!({"color": "#00ff00", "width": 60, "height": 60})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("layer.setSwitch", json!({"layers": [blur], "switch": "threeD", "value": true})).unwrap();
+    s.execute("layer.setTransform", json!({"layer": blur, "prop": "position", "value": [200, 150, 1200]})).unwrap();
+    let invis = s.execute("layer.newSolid", json!({"color": "#ff0000", "width": 40, "height": 40})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("layer.setSwitch", json!({"layers": [invis], "switch": "threeD", "value": true})).unwrap();
+    s.execute("layer.setTransform", json!({"layer": invis, "prop": "position", "value": [200, 150, 1600]})).unwrap();
+    s.execute("layer.setTransform", json!({"layer": invis, "prop": "scale", "value": [0.0, 0.0, 0.0]})).unwrap();
+    let cid = s.active_comp_id().unwrap();
+    let img = s.render(cid, effectcraft_time::Tick::ZERO, Default::default());
+    assert!(img.data.iter().all(|p| p.iter().all(|c| c.is_finite())), "non-finite pixels after setFocusToLayer");
+    // The DoF frame actually blurred (not a no-op blur): the same frame with DoF off differs.
+    s.execute("prop.set", json!({"layer": cam, "path": "cameraOptions/dof", "value": false})).unwrap();
+    let plain = s.render(cid, effectcraft_time::Tick::ZERO, Default::default());
+    assert_ne!(img.data, plain.data, "the out-of-focus layer should have blurred");
+}
+
+/// Set Focus Distance to Layer fails cleanly on a depth that isn't finite. Every stored number
+/// here is finite, but their difference overflows f64 to infinity; JSON has no infinity, so
+/// storing it would leave a project that can't be saved.
+#[test]
+fn camera_set_focus_to_layer_rejects_non_finite_depth() {
+    let mut s = comp(400, 300);
+    let t = s.execute("layer.newSolid", json!({"color": "#ffffff", "width": 50, "height": 50})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("layer.setSwitch", json!({"layers": [t], "switch": "threeD", "value": true})).unwrap();
+    s.execute("layer.setTransform", json!({"layer": t, "prop": "position", "value": [200.0, 150.0, 1e308]})).unwrap();
+    let cam = s.execute("layer.newCamera", json!({})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("layer.setTransform", json!({"layer": cam, "prop": "position", "value": [200.0, 150.0, -1e308]})).unwrap();
+    s.execute("layer.select", json!({"layers": [cam, t]})).unwrap();
+    let before = s.execute("prop.get", json!({"layer": cam, "path": "cameraOptions/focusDistance"})).unwrap()["value"].as_f64().unwrap();
+    let e = s.execute("camera.setFocusToLayer", json!({})).unwrap_err().to_string();
+    assert!(e.contains("out of range"), "{e}");
+    let after = s.execute("prop.get", json!({"layer": cam, "path": "cameraOptions/focusDistance"})).unwrap()["value"].as_f64().unwrap();
+    assert!((after - before).abs() < 1e-9, "a non-finite focus distance was written: {after}");
+    // The project still round-trips through serde (a stored infinity would come back as null).
+    let back = roundtrip(&s);
+    let f = back.comp(s.active_comp_id().unwrap()).unwrap().layer(LayerId(cam)).unwrap().props.prop("cameraOptions/focusDistance").unwrap().value.as_f64();
+    assert!((f - before).abs() < 1e-9, "serde focus distance: {f}");
+}
+
 /// An id sent as a string (`"98"`, as MCP clients often do) resolves as an id when no name matches.
 #[test]
 fn numeric_string_resolves_as_id() {

crates/engine/src/tests/text_edit.rs

@@ -199,6 +199,20 @@ fn typing_deleting_and_caret_movement() {
     assert!(s.state.text_edit.is_none());
 }
 
+/// Duplicating during a text edit moves the selection to the copy: the edit on the original ends
+/// (#2226), as in After Effects — typing must not keep editing an unselected layer.
+#[test]
+fn duplicate_during_a_text_edit_ends_the_edit() {
+    let (mut s, t) = session("Hello");
+    s.execute("text.edit", json!({"layer": t, "caret": 5})).unwrap();
+    let copy = s.execute("edit.duplicate", json!({"layers": [t]})).unwrap()[0].as_u64().unwrap();
+    assert_ne!(copy, t, "the duplicate is created");
+    assert_eq!(s.state.selected_layers, vec![effectcraft_project::LayerId(copy)], "the copy is selected");
+    assert!(s.state.text_edit.is_none(), "the edit ended with the selection move (#2226)");
+    assert_eq!(doc(&s, t).text, "Hello", "the original keeps its text");
+    assert_eq!(doc(&s, copy).text, "Hello", "and the copy carries it");
+}
+
 #[test]
 fn caret_style_applies_to_the_next_typed_text() {
     let (mut s, t) = session("ab");
@@ -928,11 +942,19 @@ fn fonts_lists_bundled_and_installed_families() {
     let r = s.execute("text.fonts", json!({"query": "noto ser", "rescan": true})).unwrap();
     assert_eq!(r["families"][0]["family"], "Noto Serif");
     // The bundled face is Regular; the OS can also provide Bold, Italic, or other faces.
-    // Compare against the independent directory inventory rather than assuming an empty OS.
-    let mut expected_styles = std::collections::BTreeSet::from(["Regular".to_string()]);
-    expected_styles.extend(installed.iter().filter(|face| face.family.eq_ignore_ascii_case("Noto Serif")).map(|face| face.style.clone()));
+    // Model `add_source()` on the independent directory inventory: a system face whose family
+    // and primary style duplicate an earlier face is skipped, with its named instances.
+    let mut expected_styles = std::collections::BTreeSet::from(["regular".to_string()]);
+    let mut retained = std::collections::BTreeSet::from([("noto serif".to_string(), "regular".to_string())]);
+    for face in installed.iter().filter(|face| face.family.eq_ignore_ascii_case("Noto Serif")) {
+        if retained.insert((face.family.to_ascii_lowercase(), face.style.to_ascii_lowercase())) {
+            expected_styles.insert(face.style.to_ascii_lowercase());
+            expected_styles.extend(face.instances.iter().map(|i| i.style.to_ascii_lowercase()));
+        }
+    }
     let styles: Vec<String> = r["families"][0]["styles"].as_array().unwrap().iter().map(|style| style.as_str().unwrap().to_string()).collect();
-    assert_eq!(styles.iter().cloned().collect::<std::collections::BTreeSet<_>>(), expected_styles);
+    // `families()` keeps the first spelling of a style that differs only in case.
+    assert_eq!(styles.iter().map(|style| style.to_ascii_lowercase()).collect::<std::collections::BTreeSet<_>>(), expected_styles);
     assert_eq!(styles.len(), expected_styles.len(), "style menu has no duplicates");
     assert!(r["families"].as_array().unwrap().iter().all(|f| f["family"].as_str().unwrap().to_lowercase().contains("noto ser")));
     // The style menus offer a family's own styles.

crates/engine/tests/it/parenting_3d_position.rs

@@ -410,12 +410,12 @@ fn parenting_static_orientation_is_exact_just_off_gimbal_lock() {
 fn parenting_animated_orientation_and_nonuniform_parent_keep_authored_pose_boundary() {
     for animated in [true, false] {
         let (mut s, p, c) = fixture(true, true);
+        // A non-uniform parent has no uniform pose to re-express, animated or not.
+        set(&mut s, p, "transform/scale", json!([120.0, 100.0, 80.0]));
         if animated {
             for (time, value) in [(0.0, json!([-8.0, 12.0, -13.0])), (1.0, json!([5.0, 18.0, 14.0]))] {
                 command(&mut s, "prop.addKey", json!({"layer":c,"path":"transform/orientation","time":time,"value":value}));
             }
-        } else {
-            set(&mut s, p, "transform/scale", json!([120.0, 100.0, 80.0]));
         }
         let layer = s.active_comp().unwrap().layer(LayerId(c)).unwrap();
         let orientation = layer.props.prop("transform/orientation").unwrap().clone();
@@ -430,6 +430,27 @@ fn parenting_animated_orientation_and_nonuniform_parent_keep_authored_pose_bound
     }
 }
 
+/// Keyed Orientation under a uniform parent is re-expressed at every key, so the child's world pose
+/// and pixels stay put at every time (the parent is Z-only, so the paths between keys stay exact too).
+#[test]
+fn parenting_uniform_parent_re_expresses_keyed_orientation() {
+    for factor in [120.0, -120.0] {
+        let (mut s, p, c) = fixture(true, false);
+        set(&mut s, p, "transform/rotation", json!(42.0));
+        set(&mut s, p, "transform/scale", json!([factor, factor, factor]));
+        for (time, value) in [(0.0, json!([-8.0, 12.0, -13.0])), (1.0, json!([5.0, 18.0, 14.0]))] {
+            command(&mut s, "prop.addKey", json!({"layer":c,"path":"transform/orientation","time":time,"value":value}));
+        }
+        let times = [0.0, 0.25, 0.5, 0.75, 1.0].map(Tick::from_seconds_f64);
+        let before = times.map(|t| world(&s, c, t));
+        let images = times.map(|t| cpu(&s, t));
+        parent(&mut s, c, Some(p), true);
+        let error = times.into_iter().zip(before).map(|(t, b)| displacement(b, world(&s, c, t))).fold(0.0, f64::max);
+        let pixels = times.into_iter().zip(&images).map(|(t, i)| diff(i, &cpu(&s, t))).fold(0.0, f32::max);
+        assert!(error < 1e-8 && pixels < 2e-5, "keyed Orientation under a uniform parent (factor {factor}): corners {error}, pixels {pixels}");
+    }
+}
+
 /// Position's temporal speed is measured along its spatial path, in parent-space units.
 #[test]
 fn parenting_uniform_parent_preserves_eased_position_at_quarter_times_and_undo() {

crates/export/src/lib.rs

@@ -376,7 +376,7 @@ async fn gif_export(job: &Cx<'_>, comp: &Comp, w: u32, h: u32, st: &mut State<'_
         let end = (i + batch).min(st.total);
         let frames: Vec<gif::Frame<'static>> = job
             .frames(comp, (i..end).collect(), |_, img| {
-                let mut px = job.pixels(&img, comp, job.output.channels, w, h);
+                let mut px = job.pixels_with(&img, comp, job.output.channels, w, h, false);
                 gif::Frame::from_rgba_speed(w as u16, h as u16, &mut px, 10)
             })
             .await;

crates/export/src/pipeline.rs

@@ -4,10 +4,8 @@
 
 use std::sync::Mutex;
 
-use effectcraft_project::render_queue::{
-    AlphaMode, Channels, ColorDepth, CurrentOrOff, EffectsMode, FrameSample, RenderLog, ResizeQuality, SwitchOverride, log_path,
-};
-use effectcraft_project::{Comp, Project};
+use effectcraft_project::render_queue::{AlphaMode, Channels, CurrentOrOff, EffectsMode, FrameSample, RenderLog, ResizeQuality, SwitchOverride, log_path};
+use effectcraft_project::{BitDepth, Comp, Project};
 use effectcraft_raster::Image;
 use effectcraft_render::{Backend, LayerCache, RenderOpts, Renderer};
 use effectcraft_time::Tick;
@@ -220,6 +218,9 @@ impl<'a> Cx<'a> {
     pub fn new(job: &'a Job<'a>) -> Cx<'a> {
         let mut project = job.project.clone();
         apply_overrides(&mut project, job);
+        // Render Settings ▸ Color Depth overrides the project's depth for the whole render (every
+        // layer and effect quantises at it), not just the finished frame (#2022).
+        project.settings.bit_depth = job.settings.color_depth.resolve(project.settings.bit_depth);
         let frame_times = (job.options.log == RenderLog::PlusPerFrameInfo).then(|| Mutex::new(Vec::new()));
         let cache = LayerCache::default();
         // With deferred readbacks, buffers computed from a missed pass's placeholders are not kept.
@@ -240,7 +241,7 @@ impl<'a> Cx<'a> {
         // compositors differ slightly, so a per-frame choice made renders differ run to run.
         let backend = if self.project.settings.gpu_acceleration { Backend::Gpu } else { Backend::Cpu };
         let opts = RenderOpts {
-            scale: s.resolution.clamp(0.01, 4.0),
+            scale: self.comp().map(|c| s.effective_scale(c)).unwrap_or_else(|| s.resolution.clamp(0.01, 4.0)),
             motion_blur: s.motion_blur_override() != SwitchOverride::OffForAll,
             guides: s.guide_layers == CurrentOrOff::Current,
             draft: s.quality == RenderQuality::Draft,
@@ -360,14 +361,6 @@ impl<'a> Cx<'a> {
                 if second == first { a } else { interleave(&a, &self.render_at(second).await, upper_first) }
             }
         };
-        let mut img = img;
-        // Color Depth: renders run at the project's depth; another depth quantises the frame.
-        let depth = self.job.settings.color_depth;
-        if depth != ColorDepth::Current
-            && let Some(levels) = depth.resolve(self.project.settings.bit_depth).levels()
-        {
-            img.quantize(levels);
-        }
         let img = self.crop_resize(img);
         if let Some(ft) = &self.frame_times {
             ft.lock().unwrap_or_else(std::sync::PoisonError::into_inner).push((i, t0.elapsed().as_secs_f64()));
@@ -384,12 +377,14 @@ impl<'a> Cx<'a> {
             return None;
         }
         let FrameSample::Progressive(t) = self.job.settings.sample(comp, i) else { return None };
-        let depth = self.job.settings.color_depth;
-        if depth != ColorDepth::Current && depth.resolve(self.project.settings.bit_depth).levels().is_some() {
+        // Above 8 bpc the colour is dithered on its way to 8 bits (`Cx::pixels`), which the
+        // accelerator's conversion doesn't do: those frames render as usual so H.264 doesn't
+        // band (#2022). The project's depth already includes Render Settings ▸ Color Depth.
+        if self.project.settings.bit_depth != BitDepth::Bpc8 {
             return None;
         }
         let om = self.job.output;
-        let scale = self.job.settings.resolution.clamp(0.01, 4.0);
+        let scale = self.job.settings.effective_scale(comp);
         let size = |n: u32| ((n as f64 * scale).round() as u32).max(1);
         if om.resize.enabled || (size(comp.width), size(comp.height)) != (w, h) || om.crop.edges(w, h, scale) != (0, 0, 0, 0) {
             return None;
@@ -435,7 +430,7 @@ impl<'a> Cx<'a> {
     /// Output Module ▸ Crop, then Resize.
     fn crop_resize(&self, img: Image) -> Image {
         let om = self.job.output;
-        let scale = self.job.settings.resolution.clamp(0.01, 4.0);
+        let scale = self.comp().map(|c| self.job.settings.effective_scale(c)).unwrap_or_else(|| self.job.settings.resolution.clamp(0.01, 4.0));
         let (t, l, b, r) = om.crop.edges(img.width, img.height, scale);
         let img = if (t, l, b, r) == (0, 0, 0, 0) { img } else { crop(&img, t, l, b, r) };
         if !om.resize.enabled {
@@ -453,12 +448,24 @@ impl<'a> Cx<'a> {
 
     /// 8-bit RGBA of the requested channels cropped/padded to `w`×`h` (codec rounding): RGB over
     /// the comp background (opaque), RGB + Alpha straight or premultiplied, or the alpha matte.
+    /// When the render runs above 8 bpc, the colour is dithered on its way to 8 bits, as After
+    /// Effects dithers colours converted down to 8 bpc for rendering and export, so gradients
+    /// rendered at 16 or 32 bpc don't band (#2022). An 8 bpc render has no finer values to
+    /// dither, so its output stays byte for byte what it was.
     pub fn pixels(&self, img: &Image, comp: &Comp, channels: Channels, w: u32, h: u32) -> Vec<u8> {
+        let dither = self.project.settings.bit_depth != BitDepth::Bpc8;
+        self.pixels_with(img, comp, channels, w, h, dither)
+    }
+
+    /// [`Cx::pixels`], dithering the colour or not (a GIF palette gains nothing from dither noise).
+    pub fn pixels_with(&self, img: &Image, comp: &Comp, channels: Channels, w: u32, h: u32, dither: bool) -> Vec<u8> {
         let px = match channels {
+            Channels::Rgb if dither => img.to_rgba8_over_dithered(comp.background),
             Channels::Rgb => img.to_rgba8_over(comp.background),
-            Channels::Rgba => match self.job.output.alpha_mode {
-                AlphaMode::Straight => img.to_rgba8(),
-                AlphaMode::Premultiplied => premultiplied8(img),
+            Channels::Rgba => match (self.job.output.alpha_mode, dither) {
+                (AlphaMode::Straight, true) => img.to_rgba8_dithered(),
+                (AlphaMode::Straight, false) => img.to_rgba8(),
+                (AlphaMode::Premultiplied, _) => premultiplied8(img, dither),
             },
             Channels::Alpha => img
                 .data
@@ -619,15 +626,22 @@ fn bicubic(src: &Image, w: u32, h: u32) -> Image {
     out
 }
 
-/// Premultiplied 8-bit RGBA (colour matted with black).
-fn premultiplied8(img: &Image) -> Vec<u8> {
-    img.data
-        .iter()
-        .flat_map(|p| {
-            let a = p[3].clamp(0.0, 1.0);
-            [0, 1, 2].map(|c| (p[c].clamp(0.0, a) * 255.0 + 0.5) as u8).into_iter().chain([(a * 255.0 + 0.5) as u8])
-        })
-        .collect()
+/// Premultiplied 8-bit RGBA (colour matted with black), the colour dithered when `dither`.
+fn premultiplied8(img: &Image, dither: bool) -> Vec<u8> {
+    let w = img.width.max(1) as usize;
+    let mut out = Vec::with_capacity(img.data.len() * 4);
+    for (i, p) in img.data.iter().enumerate() {
+        let a = p[3].clamp(0.0, 1.0);
+        let a8 = (a * 255.0 + 0.5) as u8;
+        let (x, y) = ((i % w) as u32, (i / w) as u32);
+        for c in 0..3 {
+            let v = p[c].clamp(0.0, a);
+            // Dither may round up past the rounded alpha; premultiplied colour never exceeds it.
+            out.push(if dither { effectcraft_raster::dither_u8(v, x, y).min(a8) } else { (v * 255.0 + 0.5) as u8 });
+        }
+        out.push(a8);
+    }
+    out
 }
 
 #[cfg(test)]
@@ -636,6 +650,19 @@ mod tests {
     use rayon::prelude::*;
     use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
 
+    /// Dither may round a colour up while alpha rounds down; premultiplied colour stays at or
+    /// below the written alpha at every pixel.
+    #[test]
+    fn dithered_premultiplied_colour_never_exceeds_alpha() {
+        let v = 100.25 / 255.0;
+        let img = Image::filled(64, 64, [v, v, v, v]);
+        let px = premultiplied8(&img, true);
+        assert!(px.as_chunks::<4>().0.iter().all(|p| p[..3].iter().all(|c| *c <= p[3])), "a colour byte is above its alpha");
+        assert!(px.as_chunks::<4>().0.iter().all(|p| p[3] == 100));
+        let plain = premultiplied8(&img, false);
+        assert!(plain.as_chunks::<4>().0.iter().all(|p| *p == [100, 100, 100, 100]));
+    }
+
     /// Frames `0..n` through [`map_frames`] with `cap`, recording the most running at once.
     fn run_capped(n: u64, cap: Option<usize>) -> (Vec<u64>, usize) {
         use std::sync::atomic::{AtomicUsize, Ordering};

crates/export/tests/it/banding.rs

@@ -0,0 +1,156 @@
+//! Gradients exported at 16 bpc (or with a 16 bpc Color Depth override) don't band (#2022): the
+//! float frame is dithered on its way to 8 bits, and the Render Settings' Color Depth reaches the
+//! render itself.
+
+use std::sync::{Arc, Mutex};
+
+use effectcraft_color::Label;
+use effectcraft_export::render_queue::*;
+use effectcraft_export::{Job, JobOptions, Sink, export};
+use effectcraft_keyframe::Value;
+use effectcraft_project::build::{self, Ids};
+use effectcraft_project::{BitDepth, Comp, ItemId, ItemKind, LayerSource, Project, Solid};
+use effectcraft_render::NoFootage;
+use effectcraft_time::{FrameRate, Tick};
+
+const W: u32 = 1024;
+const H: u32 = 16;
+/// The ramp runs from this grey to `HI` across the comp: about 25 eight-bit codes in 1024 px,
+/// so plain rounding makes bands about 40 px wide.
+const LO: f64 = 0.20;
+const HI: f64 = 0.30;
+/// Width of the column blocks whose mean is compared with the ideal ramp.
+const WINDOW: u32 = 8;
+
+/// A grey horizontal ramp over a comp of the given project depth.
+fn ramp_project(depth: BitDepth) -> (Project, ItemId) {
+    let mut p = Project::default();
+    p.settings.bit_depth = depth;
+    let mut comp = Comp::new(W, H, FrameRate::new(25, 1), Tick::from_seconds_f64(1.0));
+    comp.background = [0.0, 0.0, 0.0];
+    let sid = p.add_item("Ramp", Label::Red, None, ItemKind::Solid(Solid { color: [1.0, 1.0, 1.0], width: W, height: H, pixel_aspect: 1.0 }));
+    let mut layer = build::layer(&mut p, &comp, "Ramp", LayerSource::Solid { item: sid }, (W, H), None);
+    let spec = effectcraft_effects::find("ec.generate.gradientramp").expect("gradient ramp effect");
+    let mut next = p.next_id;
+    let mut group = effectcraft_effects::instantiate(spec, &mut Ids(&mut next), spec.name, [W as f64, H as f64]);
+    p.next_id = next;
+    for (k, v) in [
+        ("start", Value::Vec2([0.0, 0.0])),
+        ("end", Value::Vec2([W as f64, 0.0])),
+        ("startColor", Value::Color([LO, LO, LO, 1.0])),
+        ("endColor", Value::Color([HI, HI, HI, 1.0])),
+    ] {
+        group.get_mut(k).expect("ramp parameter").value = v;
+    }
+    layer.props.sub_mut("effects").expect("effects group").children.push(group.into());
+    comp.layers.push(layer);
+    let cid = p.add_item("Comp", Label::Sandstone, None, ItemKind::Comp(comp.into()));
+    (p, cid)
+}
+
+/// Export frame 0 as PNG with the Render Settings' Color Depth `depth` and return the grey of
+/// every row.
+fn export_rows(p: &Project, cid: ItemId, depth: ColorDepth) -> Vec<Vec<u8>> {
+    let files: Arc<Mutex<Vec<(String, Vec<u8>)>>> = Default::default();
+    let f = files.clone();
+    let sink: Box<Sink> = Box::new(move |path: &str, data: Vec<u8>| f.lock().unwrap().push((path.to_string(), data)));
+    let settings =
+        RenderSettings { time_span: TimeSpan::Custom { start: Tick::ZERO, end: Tick::from_seconds_f64(0.04) }, color_depth: depth, ..Default::default() };
+    let om = OutputModule::for_format(OutputFormat::PngSequence);
+    let job = Job {
+        project: p,
+        footage: &NoFootage,
+        expr: None,
+        accel: None,
+        comp: cid,
+        settings: &settings,
+        output: &om,
+        path: "/banding/f_[#####].png",
+        sink: Some(&*sink),
+        options: JobOptions::default(),
+        nested_switches: true,
+    };
+    export(&job, &mut |_| true).expect("export");
+    let files = files.lock().unwrap();
+    let (_, png) = files.iter().find(|(path, _)| path.ends_with(".png")).expect("a PNG");
+    let img = image::load_from_memory(png).expect("png").to_rgba8();
+    (0..H).map(|y| (0..W).map(|x| img.get_pixel(x, y).0[1]).collect()).collect()
+}
+
+/// The ideal ramp at column `x`, in 8-bit codes.
+fn ideal(x: f64) -> f64 {
+    255.0 * (LO + (HI - LO) * (x + 0.5) / W as f64)
+}
+
+/// Longest run of equal neighbours in the row: a band's width.
+fn longest_run(row: &[u8]) -> usize {
+    let (mut best, mut run) = (1, 1);
+    for w in row.windows(2) {
+        run = if w[0] == w[1] { run + 1 } else { 1 };
+        best = best.max(run);
+    }
+    best
+}
+
+/// Horizontal neighbours with different values, over all rows: ~25 per row when every band is a
+/// flat step, hundreds when the steps are dithered.
+fn transitions(rows: &[Vec<u8>]) -> usize {
+    rows.iter().map(|r| r.windows(2).filter(|w| w[0] != w[1]).count()).sum()
+}
+
+/// Largest difference, in 8-bit codes, between the mean of a `WINDOW`-column block over all rows
+/// and the ideal ramp's mean over it. Plain rounding leaves up to ~0.4 codes of it beside a step
+/// edge; dither averages it away (its noise on a mean of `WINDOW * H` samples is under 0.05).
+fn worst_window_error(rows: &[Vec<u8>]) -> f64 {
+    (0..W / WINDOW)
+        .map(|i| {
+            let (x0, x1) = ((i * WINDOW) as usize, ((i + 1) * WINDOW) as usize);
+            let sum: f64 = rows.iter().flat_map(|r| &r[x0..x1]).map(|&v| v as f64).sum();
+            let mean = sum / (rows.len() * (x1 - x0)) as f64;
+            (mean - ideal((x0 + x1) as f64 / 2.0 - 1.0)).abs()
+        })
+        .fold(0.0, f64::max)
+}
+
+#[test]
+fn a_16_bpc_gradient_export_is_dithered() {
+    let (p, cid) = ramp_project(BitDepth::Bpc16);
+    let rows = export_rows(&p, cid, ColorDepth::Current);
+    let (steps, err) = (transitions(&rows), worst_window_error(&rows));
+    eprintln!("16 bpc project: {steps} transitions, worst {WINDOW}-px mean error {err:.3} codes");
+    // Undithered there are ~25 flat steps per row (400 transitions) and the block means are off
+    // by up to ~0.4 codes.
+    assert!(steps > 2000, "the steps survive: {steps} transitions");
+    assert!(err < 0.25, "the local mean is off by {err} codes");
+    // Dither never moves a value a whole code from the ideal ramp.
+    for row in &rows {
+        for (x, &v) in row.iter().enumerate() {
+            let want = ideal(x as f64);
+            assert!((v as f64 - want).abs() < 1.05, "x {x}: {v} vs {want}");
+        }
+    }
+}
+
+#[test]
+fn the_export_is_the_same_every_time() {
+    let (p, cid) = ramp_project(BitDepth::Bpc16);
+    assert_eq!(export_rows(&p, cid, ColorDepth::Current), export_rows(&p, cid, ColorDepth::Current));
+}
+
+#[test]
+fn the_render_color_depth_reaches_the_render() {
+    // An 8 bpc project renders every layer at 8 bits: flat steps, nothing for the output to dither.
+    let (p, cid) = ramp_project(BitDepth::Bpc8);
+    let banded = export_rows(&p, cid, ColorDepth::Current);
+    assert!(longest_run(&banded[0]) >= 30, "an 8 bpc render is quantised before export");
+    assert!(transitions(&banded) < 16 * 30);
+    // The Render Settings' 16 bpc depth overrides the project's: the render keeps its precision
+    // until the final conversion, which dithers.
+    let deep = export_rows(&p, cid, ColorDepth::Bpc16);
+    let (steps, err) = (transitions(&deep), worst_window_error(&deep));
+    eprintln!("8 bpc project, 16 bpc render: {steps} transitions, worst {WINDOW}-px mean error {err:.3} codes");
+    assert!(steps > 2000 && err < 0.25, "a 16 bpc render still bands: {steps} transitions, error {err}");
+    // And 8 bpc on a 16 bpc project renders at 8 bits.
+    let (p16, cid16) = ramp_project(BitDepth::Bpc16);
+    assert_eq!(export_rows(&p16, cid16, ColorDepth::Bpc8), banded);
+}

crates/export/tests/it/h264_gpu_yuv.rs

@@ -6,7 +6,7 @@ use std::path::{Path, PathBuf};
 use std::sync::atomic::{AtomicUsize, Ordering};
 
 use effectcraft_color::Label;
-use effectcraft_export::render_queue::{OutputFormat, OutputModule, RenderSettings, TimeSpan};
+use effectcraft_export::render_queue::{ColorDepth, OutputFormat, OutputModule, RenderSettings, TimeSpan};
 use effectcraft_export::{Job, export};
 use effectcraft_project::{Comp, ItemId, ItemKind, LayerSource, Project, Solid, build};
 use effectcraft_raster::Image;
@@ -147,6 +147,20 @@ fn frames_the_accelerator_cannot_take_fall_back_to_rgba() {
     assert!(a == c);
 }
 
+/// Above 8 bpc the colour is dithered on its way to 8 bits, which the accelerator's planes
+/// don't do: those frames take the RGBA path, so an H.264 export doesn't band (#2022).
+#[test]
+fn renders_above_8_bpc_skip_the_planes() {
+    let d = out_dir("h264-gpu-yuv-16bpc");
+    let (p, cid) = project();
+    let s = RenderSettings { time_span: TimeSpan::LengthOfComp, color_depth: ColorDepth::Bpc16, ..Default::default() };
+    let yuv = Fake::new(true, false, usize::MAX);
+    let a = run(&p, cid, Some(&yuv), &s, &d.join("yuv.mp4"));
+    let c = run(&p, cid, None, &s, &d.join("cpu.mp4"));
+    assert_eq!(yuv.yuv_frames.load(Ordering::SeqCst), 0, "no planes asked for above 8 bpc");
+    assert!(a == c);
+}
+
 /// With deferred readbacks the export keeps rendering frames in passes (`Cx::frames`), never
 /// through the blocking per-frame path the planes use.
 #[test]

crates/export/tests/it/main.rs

@@ -1,6 +1,7 @@
 //! The crate's integration tests, one binary (each module is a former `tests/<name>.rs`).
 
 mod audio_sample_positions;
+mod banding;
 mod h264_gpu_yuv;
 mod hevc_av1_roundtrip;
 #[cfg(not(target_arch = "wasm32"))]

crates/expr/src/host.rs

@@ -10,7 +10,7 @@
 use effectcraft_geom::{Mat3, Mat4};
 use effectcraft_keyframe::Value;
 use effectcraft_project::{Comp, ItemId, ItemKind, Layer, LayerId, LayerSource, Node, PropGroup, Property};
-use effectcraft_render::{EvalCtx, source_size};
+use effectcraft_render::EvalCtx;
 use effectcraft_time::Tick;
 
 /// A name-or-index argument (`layer("A")`, `layer(2)`, `effect(1)`).
@@ -299,7 +299,17 @@ impl<'a> Resolver<'a> {
     }
     fn ctx_at(&self, c: u64, t: f64) -> Option<EvalCtx<'a>> {
         let comp = self.comp(c)?;
-        Some(EvalCtx { project: self.ctx.project, comp_id: ItemId(c), comp, time: Tick::from_seconds_f64(t), expr: self.ctx.expr, footage: self.ctx.footage })
+        let same_comp = c == self.ctx.comp_id.0;
+        Some(EvalCtx {
+            project: self.ctx.project,
+            comp_id: ItemId(c),
+            comp,
+            time: Tick::from_seconds_f64(t),
+            expr: self.ctx.expr,
+            footage: self.ctx.footage,
+            property_overrides: if same_comp { self.ctx.property_overrides } else { &[] },
+            media_overrides: if same_comp { self.ctx.media_overrides } else { &[] },
+        })
     }
     fn prop(&self, c: u64, l: u64, path: &str) -> Option<(&'a Layer, &'a Property)> {
         let layer = self.layer(c, l)?;
@@ -372,7 +382,7 @@ impl<'a> Resolver<'a> {
             Req::LayerInfo { comp, layer } => {
                 let c = self.comp(*comp)?;
                 let l = self.layer(*comp, *layer)?;
-                let (mut w, mut h) = source_size(project, l);
+                let (mut w, mut h) = self.ctx_at(*comp, self.ctx.time.seconds())?.source_size(l);
                 if w == 0 || h == 0 {
                     (w, h) = (c.width, c.height);
                 }
@@ -467,7 +477,7 @@ impl<'a> Resolver<'a> {
                         }
                     }
                     _ => {
-                        let (w, h) = source_size(project, l);
+                        let (w, h) = ctx.source_size(l);
                         [0.0, 0.0, w as f64, h as f64]
                     }
                 };
@@ -501,7 +511,12 @@ impl<'a> Resolver<'a> {
             Req::SourceInfo { comp, layer } => {
                 let c = self.comp(*comp)?;
                 let l = self.layer(*comp, *layer)?;
-                let it = project.item(l.source.item()?)?;
+                let ctx = self.ctx_at(*comp, self.ctx.time.seconds())?;
+                let item = match &l.source {
+                    LayerSource::Footage { item } => ctx.media_item(l, *item),
+                    _ => l.source.item()?,
+                };
+                let it = project.item(item)?;
                 let (kind, aspect, frame, duration) = match &it.kind {
                     ItemKind::Comp(nc) => ("comp", nc.pixel_aspect, nc.frame_duration().seconds(), nc.duration.seconds()),
                     ItemKind::Footage(f) => ("footage", f.pixel_aspect, f.frame_rate.frame_duration().seconds(), f.duration.seconds()),

crates/expr/src/lib.rs

@@ -17,7 +17,8 @@
 //!   `sourceRectAtTime`), property methods (`valueAtTime`, `velocityAtTime`, `speedAtTime`, `key`,
 //!   `nearestKey`, `numKeys`, `wiggle`, `temporalWiggle`, `smooth`, `loopIn/Out[Duration]`) and the
 //!   global helpers (`linear`/`ease`/`easeIn`/`easeOut`, `random`/`gaussRandom`/`seedRandom`/
-//!   `noise`, vector maths, `clamp`, `lookAt`, time and colour conversions, `posterizeTime`).
+//!   `noise`, vector maths, `clamp`, `lookAt`, time and colour conversions, `posterizeTime`),
+//!   plus `bezier`, a CSS-style cubic-Bezier easing helper that After Effects does not have.
 //! * **Determinism**: `wiggle` and `random` are seeded by layer index, property uid (and time /
 //!   `seedRandom`), so frames render identically on every thread and platform.
 //! * **Runtime**: one boa `Context` per thread with compiled scripts cached by text. Scripts read
@@ -162,7 +163,16 @@ fn evaluate_out(
         return Err("Error: expressions reference each other too deeply (circular reference?)".into());
     }
     budget_left()?;
-    let ctx = EvalCtx { project: ctx.project, comp_id: ctx.comp_id, comp: ctx.comp, time: ctx.time, expr: Some(host), footage: ctx.footage };
+    let ctx = EvalCtx {
+        project: ctx.project,
+        comp_id: ctx.comp_id,
+        comp: ctx.comp,
+        time: ctx.time,
+        expr: Some(host),
+        footage: ctx.footage,
+        property_overrides: ctx.property_overrides,
+        media_overrides: ctx.media_overrides,
+    };
     let comp = ctx.comp_id.0;
     let path = layer.props.path_of(prop.uid).unwrap_or_else(|| format!("@{}", prop.uid));
     let resolver = Resolver { ctx, own: Own { comp, layer, prop, path: path.clone() } };

crates/expr/src/prelude.js

@@ -207,6 +207,60 @@ function ease() { return __interp(__ease, arguments); }
 function easeIn() { return __interp(__easeIn, arguments); }
 function easeOut() { return __interp(__easeOut, arguments); }
 
+// Cubic-Bezier easing (the CSS cubic-bezier() shape): [x1, y1, x2, y2], with x1 / x2 in 0..1
+// and y1 / y2 free (overshoot included). Solves x(u) = x by Newton–Raphson, then by bisection
+// when Newton leaves 0..1 or the derivative vanishes, and returns y(u). A curve that is not four
+// finite numbers is linear, never an error.
+function __cubicBezier(curve) {
+  var x1, y1, x2, y2;
+  if (Array.isArray(curve) && curve.length === 4) {
+    x1 = curve[0]; y1 = curve[1]; x2 = curve[2]; y2 = curve[3];
+  }
+  if (typeof x1 !== 'number' || typeof y1 !== 'number' || typeof x2 !== 'number' || typeof y2 !== 'number' ||
+      !isFinite(x1) || !isFinite(y1) || !isFinite(x2) || !isFinite(y2)) {
+    return __lin;
+  }
+  x1 = Math.max(0, Math.min(1, x1));
+  x2 = Math.max(0, Math.min(1, x2));
+  function bx(u) { var v = 1 - u; return 3 * v * v * u * x1 + 3 * v * u * u * x2 + u * u * u; }
+  function dbx(u) { var v = 1 - u; return 3 * v * v * x1 + 6 * v * u * (x2 - x1) + 3 * u * u * (1 - x2); }
+  function by(u) { var v = 1 - u; return 3 * v * v * u * y1 + 3 * v * u * u * y2 + u * u * u; }
+  function dby(u) { var v = 1 - u; return 3 * v * v * y1 + 6 * v * u * (y2 - y1) + 3 * u * u * (1 - y2); }
+  return function (x) {
+    if (x <= 0) return 0;
+    if (x >= 1) return 1;
+    var u = x;
+    for (var i = 0; i < 8; i++) {
+      var f = bx(u) - x;
+      var d = dbx(u);
+      if (Math.abs(d) < 1e-12) break;
+      // Stop when the *value* is accurate: near the endpoints dy/dx is steep, so a residual in x
+      // alone can still mean a visible error in y (f * dy/dx estimates it).
+      if (Math.abs(f * dby(u) / d) < 1e-9) return by(u);
+      var n = u - f / d;
+      if (!(n >= 0 && n <= 1)) break;
+      u = n;
+    }
+    var lo = 0, hi = 1;
+    for (var j = 0; j < 60; j++) {
+      var mid = (lo + hi) / 2;
+      if (bx(mid) < x) lo = mid; else hi = mid;
+    }
+    return by((lo + hi) / 2);
+  };
+}
+
+// bezier(t, tMin, tMax, value1, value2, curve), or bezier(t, value1, value2, curve): the curve is
+// the sixth / fourth argument. Read it by position, not from the end: when it is missing or
+// unusable, the interpolation falls back to linear without consuming the last value.
+function bezier() {
+  var a = arguments, n = a.length;
+  if (n >= 6) return __interp(__cubicBezier(a[5]), [a[0], a[1], a[2], a[3], a[4]]);
+  if (n === 5) return __interp(__lin, [a[0], a[1], a[2], a[3], a[4]]);
+  if (n === 4) return __interp(__cubicBezier(a[3]), [a[0], a[1], a[2]]);
+  return __interp(__lin, [a[0], a[1], a[2]]);
+}
+
 // ---------------------------------------------------------------------------------------------
 // Random numbers and noise.
 

crates/expr/src/tests.rs

@@ -314,8 +314,78 @@ fn interpolation_with_arrays() {
     assert_eq!(f.pos("ease(time, 0, 1, [0, 0], [100, 50])", 1.0), [100.0, 50.0, 0.0]);
 }
 
-// ---- object model -----------------------------------------------------------------------------
+#[test]
+fn cubic_bezier_curves() {
+    let f = fx();
+    // ease(t, …) is cubic-bezier(1/3, 0, 2/3, 1): x(u) = u and y(u) = 3u² - 2u³.
+    assert_close!(f.num("bezier(0.25, 0, 1, 0, 100, [0.3333333333333333, 0, 0.6666666666666666, 1])", 0.0), f.num("ease(0.25, 0, 1, 0, 100)", 0.0));
+    assert_close!(f.num("bezier(0.5, 0, 1, 0, 100, [0.3333333333333333, 0, 0.6666666666666666, 1])", 0.0), 50.0);
+    // Symmetric ease-in-out: slower at both ends, faster in the middle.
+    let early = f.num("bezier(0.25, 0, 1, 0, 100, [0.42, 0, 0.58, 1])", 0.0);
+    let late = f.num("bezier(0.75, 0, 1, 0, 100, [0.42, 0, 0.58, 1])", 0.0);
+    assert!(early < 25.0 && late > 75.0, "ease-in-out: {early}, {late}");
+    // Control points on the diagonal are linear.
+    assert_close!(f.num("bezier(0.3, 0, 1, 0, 100, [0, 0, 1, 1])", 0.0), 30.0);
+    // t is clamped to tMin..tMax; tMin == tMax behaves like the other helpers.
+    assert_close!(f.num("bezier(-1, 0, 1, 0, 100, [0.42, 0, 0.58, 1])", 0.0), 0.0);
+    assert_close!(f.num("bezier(2, 0, 1, 0, 100, [0.42, 0, 0.58, 1])", 0.0), 100.0);
+    assert_close!(f.num("bezier(5, 2, 2, 0, 100, [0.42, 0, 0.58, 1])", 0.0), 100.0);
+}
 
+#[test]
+fn cubic_bezier_short_form_arrays_and_fallbacks() {
+    let f = fx();
+    // Short form: no tMin / tMax.
+    assert_close!(f.num("bezier(0.25, 10, 20, [0, 0, 1, 1])", 0.0), 12.5);
+    assert_eq!(f.pos("bezier(time, 0, 1, [0, 0], [100, 50], [0.42, 0, 0.58, 1])", 1.0), [100.0, 50.0, 0.0]);
+    // y outside 0..1 overshoots, as CSS allows.
+    let over = f.num("bezier(0.5, 0, 1, 0, 100, [0.5, 2, 0.5, 2])", 0.0);
+    assert!(over > 100.0, "overshoot: {over}");
+    // A curve that is not four finite numbers falls back to linear instead of throwing.
+    assert_close!(f.num("bezier(0.5, 0, 1, 0, 100, [1, 0])", 0.0), 50.0);
+    assert_close!(f.num("bezier(0.5, 0, 1, 0, 100, 'ease')", 0.0), 50.0);
+    // A missing or unusable curve must not consume the last value: read the curve by position.
+    assert_close!(f.num("bezier(0.5, 0, 1, 0, 100)", 0.0), 50.0);
+    assert_close!(f.num("bezier(0.5, 0, 100)", 0.0), 50.0);
+    assert_close!(f.num("bezier(0.5, 0, 100, [1, 0])", 0.0), 50.0);
+    let v = f.ev(f.shape, "contents/#1/contents/fill/color", "bezier(0.5, 0, 1, [0, 0, 0, 1], [1, 1, 1, 1])", 0.0).unwrap();
+    assert_eq!(v, Value::Color([0.5, 0.5, 0.5, 1.0]));
+    // Exactly four values are a curve; extra ones mean the curve is malformed, so linear.
+    assert_close!(f.num("bezier(0.5, 0, 1, 0, 100, [0.42, 0, 0.58, 1, 0])", 0.0), 50.0);
+    assert_close!(f.num("bezier(0.5, 0, 1, 0, 100, [0.42, 0, 0.58, 1, 2, 3])", 0.0), 50.0);
+    // x control points outside 0..1 are clamped, as CSS requires.
+    let v = f.num("bezier(0.5, 0, 1, 0, 100, [-1, 0, 2, 1])", 0.0);
+    assert!(v.is_finite(), "clamped curve: {v}");
+}
+
+#[test]
+fn cubic_bezier_is_accurate_near_the_endpoints() {
+    /// The value the curve reaches at `x`, by bisection on its monotone x(u).
+    fn reference(x1: f64, y1: f64, x2: f64, y2: f64, x: f64) -> f64 {
+        let bx = |u: f64| 3.0 * (1.0 - u) * (1.0 - u) * u * x1 + 3.0 * (1.0 - u) * u * u * x2 + u * u * u;
+        let by = |u: f64| 3.0 * (1.0 - u) * (1.0 - u) * u * y1 + 3.0 * (1.0 - u) * u * u * y2 + u * u * u;
+        let (mut lo, mut hi) = (0.0f64, 1.0f64);
+        for _ in 0..100 {
+            let mid = 0.5 * (lo + hi);
+            if bx(mid) < x {
+                lo = mid;
+            } else {
+                hi = mid;
+            }
+        }
+        by(0.5 * (lo + hi))
+    }
+    // Steep curves: a residual in x is not a residual in y near the endpoints (dy/dx is in the
+    // thousands), so the solver stops on the estimated y error instead.
+    let f = fx();
+    for (c, x) in [([0.0, 1000.0, 1.0, 1.0], 1e-6), ([0.0, 100.0, 1.0, 0.0], 1e-9), ([0.8, -500.0, 1.0, 1.0], 0.999999)] {
+        let got = f.num(&format!("bezier({x}, 0, 1, [{}, {}, {}, {}])", c[0], c[1], c[2], c[3]), 0.0);
+        let want = reference(c[0], c[1], c[2], c[3], x);
+        assert!((got - want).abs() < 1e-6, "curve {c:?} at {x}: {got} vs {want}");
+    }
+}
+
+// ---- object model -----------------------------------------------------------------------------
 #[test]
 fn comp_attributes() {
     let f = fx();
@@ -908,6 +978,49 @@ fn source_rect_at_time() {
     assert!((s[0] + 31.0).abs() < 2.0 && (s[1] + 16.0).abs() < 2.0 && (s[2] - 62.0).abs() < 3.0, "{s:?}");
 }
 
+#[test]
+fn source_dimensions_follow_media_replacement() {
+    let mut p = Project::default();
+    let comp = Comp::new(200, 100, FrameRate::FPS_30, Tick::from_seconds_f64(2.0));
+    let cid = p.add_item("Main", Label::Sandstone, None, ItemKind::Comp(comp.clone().into()));
+    let footage = |p: &mut Project, name: &str, width, height| {
+        p.add_item(
+            name,
+            Label::SeaFoam,
+            None,
+            ItemKind::Footage(effectcraft_project::Footage {
+                path: name.into(),
+                kind: effectcraft_project::FootageKind::Still,
+                width,
+                height,
+                has_video: true,
+                ..Default::default()
+            }),
+        )
+    };
+    let original = footage(&mut p, "original.png", 100, 80);
+    let replacement = footage(&mut p, "replacement.png", 30, 40);
+    let mut l = build::layer(&mut p, &comp, "Clip", LayerSource::Footage { item: original }, (100, 80), None);
+    l.props.prop_mut(ROT).unwrap().expr =
+        Some(Expression { text: "thisLayer.width + thisLayer.height + thisLayer.source.width + sourceRectAtTime().width".into(), enabled: true });
+    let lid = l.id;
+    p.comp_mut(cid).unwrap().layers.push(l);
+    let c = p.comp(cid).unwrap();
+    let l = c.layer(lid).unwrap();
+    let media = effectcraft_render::MediaOverride::new(lid, replacement);
+    let ctx = EvalCtx {
+        project: &p,
+        comp_id: cid,
+        comp: c,
+        time: Tick::ZERO,
+        expr: Some(&Expressions),
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[media],
+    };
+    assert_eq!(ctx.value(l, l.props.prop(ROT).unwrap()), Value::Scalar(130.0));
+}
+
 // ---- colour -----------------------------------------------------------------------------------
 
 #[test]
@@ -1115,7 +1228,16 @@ fn text_expression_selector_values() {
     let sel_of = |p: &Project| {
         let c = p.comp(cid).unwrap();
         let l = c.layer(lid).unwrap();
-        let ctx = EvalCtx { project: p, comp_id: cid, comp: c, time: Tick::ZERO, expr: Some(&Expressions), footage: None };
+        let ctx = EvalCtx {
+            project: p,
+            comp_id: cid,
+            comp: c,
+            time: Tick::ZERO,
+            expr: Some(&Expressions),
+            footage: None,
+            property_overrides: &[],
+            media_overrides: &[],
+        };
         let doc = effectcraft_render::text::source_text(&ctx, l).unwrap();
         let lay = effectcraft_text::layout_doc(&doc);
         let anim = l.props.group("text/animators/#1").unwrap();

crates/expr/src/tests/fuzz.rs

@@ -93,6 +93,8 @@ const SEEDS: &[&str] = &[
     "linear(time, 0, 1, 0, 100)",
     "ease(time, 0, 2, [0, 0], [100, 50])",
     "easeIn(time, 0, 1, 0, 360) + easeOut(time, 1, 2, 0, 10)",
+    "bezier(time, 0, 1, 0, 100, [0.42, 0, 0.58, 1])",
+    "bezier(time, [0, 0], [100, 50], [0.25, 0.1, 0.25, 1])",
     "clamp(value * 2, 0, 100)",
     "length([0, 0], [3, 4]) + dot([1, 0], [0, 1]) + cross([1, 0, 0], [0, 1, 0])[2]",
     "normalize([3, 4])[0] * degreesToRadians(180)",

crates/gpu/src/bokeh.rs

@@ -10,8 +10,9 @@ use crate::context::{Enc, GpuImage, Params};
 
 /// Blur `src` (an unpadded plane buffer) as `d` says. Returns the padded, blurred image.
 pub(crate) fn apply(e: &mut Enc, src: &GpuImage, d: &PlaneDof) -> Option<GpuImage> {
-    let (w, h) = (src.width + 2 * d.pad, src.height + 2 * d.pad);
-    if !e.g.fits(w + 1, h) || d.radius.len() != w as usize * h as usize || d.levels.is_empty() {
+    // Saturating, so an oversized padding is refused by `fits` below instead of wrapping around.
+    let (w, h) = (src.width.saturating_add(d.pad.saturating_mul(2)), src.height.saturating_add(d.pad.saturating_mul(2)));
+    if !e.g.fits(w.saturating_add(1), h) || d.radius.len() != w as usize * h as usize || d.levels.is_empty() {
         return None;
     }
     let padded = e.image(w, h);

crates/gpu/src/tests/adv3d.rs

@@ -96,7 +96,16 @@ pub(crate) fn scene_project() -> (Project, ItemId) {
 
 pub(crate) fn scene(p: &Project, cid: ItemId) -> Scene {
     let r = Renderer::new(p, &NoFootage, RenderOpts::default());
-    let ctx = EvalCtx { project: p, comp_id: cid, comp: p.comp(cid).unwrap(), time: Tick::ZERO, expr: None, footage: None };
+    let ctx = EvalCtx {
+        project: p,
+        comp_id: cid,
+        comp: p.comp(cid).unwrap(),
+        time: Tick::ZERO,
+        expr: None,
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let run: Vec<&effectcraft_project::Layer> = ctx.comp.layers.iter().rev().filter(|l| l.is_3d() && l.has_video()).collect();
     adv::scene_of(&r, &ctx, &run, (ctx.comp.width, ctx.comp.height))
 }
@@ -277,7 +286,16 @@ pub(crate) fn off_share(a: &[[f32; 4]], b: &[[f32; 4]]) -> (f64, f32) {
 }
 
 pub(crate) fn run_of(p: &Project, cid: ItemId) -> (EvalCtx<'_>, Vec<&effectcraft_project::Layer>) {
-    let ctx = EvalCtx { project: p, comp_id: cid, comp: p.comp(cid).unwrap(), time: Tick::ZERO, expr: None, footage: None };
+    let ctx = EvalCtx {
+        project: p,
+        comp_id: cid,
+        comp: p.comp(cid).unwrap(),
+        time: Tick::ZERO,
+        expr: None,
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let run: Vec<&effectcraft_project::Layer> = ctx.comp.layers.iter().rev().filter(|l| l.is_3d() && l.has_video()).collect();
     (ctx, run)
 }

crates/gpu/src/walk.rs

@@ -89,7 +89,7 @@ fn draw_comp<'a>(e: &mut Enc, r: &Renderer<'a>, ctx: &EvalCtx<'a>, canvas: &mut
             i = j;
         } else {
             match r.collapsed(ctx, visible[i]) {
-                Some(item) => draw_collapsed(e, r, ctx, visible[i], item, canvas)?,
+                Some(collapsed) => draw_collapsed(e, r, ctx, visible[i], &collapsed, canvas)?,
                 None => draw_layer(e, r, ctx, visible[i], canvas)?,
             }
             i += 1;
@@ -187,19 +187,26 @@ fn draw_split(e: &mut Enc, r: &Renderer, ctx: &EvalCtx, split: &effectcraft_rend
     Some(cv)
 }
 
-fn draw_collapsed<'a>(e: &mut Enc, r: &Renderer<'a>, ctx: &EvalCtx<'a>, layer: &Layer, item: ItemId, canvas: &mut GpuImage) -> Option<()> {
+fn draw_collapsed<'a>(
+    e: &mut Enc,
+    r: &Renderer<'a>,
+    ctx: &EvalCtx<'a>,
+    layer: &'a Layer,
+    collapsed: &effectcraft_render::Collapsed,
+    canvas: &mut GpuImage,
+) -> Option<()> {
     let opacity = r.layer_opacity(ctx, layer);
     if opacity <= 0.0 {
         return Some(());
     }
     let matte = r.track_matte(ctx, layer).is_some();
     if layer.blend_mode == BlendMode::Normal && !matte && !layer.preserve_transparency {
-        if let Some((sub, nctx)) = r.collapse_into(ctx, layer, item, opacity) {
+        if let Some((sub, nctx)) = r.collapse_into(ctx, layer, collapsed, opacity) {
             draw_comp(e, &sub, &nctx, canvas)?;
         }
         return Some(());
     }
-    let Some((sub, nctx)) = r.collapse_into(ctx, layer, item, 1.0) else { return Some(()) };
+    let Some((sub, nctx)) = r.collapse_into(ctx, layer, collapsed, 1.0) else { return Some(()) };
     let mut iso = e.zeros(canvas.width, canvas.height);
     draw_comp(e, &sub, &nctx, &mut iso)?;
     composite_iso(e, r, ctx, layer, iso, canvas, opacity)

crates/host/src/tests.rs

@@ -269,7 +269,16 @@ fn value(s: &effectcraft_engine::Session, l: u64, path: &str) -> effectcraft_eng
     let cid = s.active_comp_id().unwrap();
     let comp = s.project.comp(cid).unwrap();
     let layer = comp.layer(effectcraft_engine::project::LayerId(l)).unwrap();
-    let ctx = effectcraft_engine::render::EvalCtx { project: &s.project, comp_id: cid, comp, time: Default::default(), expr: s.expr.as_deref(), footage: None };
+    let ctx = effectcraft_engine::render::EvalCtx {
+        project: &s.project,
+        comp_id: cid,
+        comp,
+        time: Default::default(),
+        expr: s.expr.as_deref(),
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     ctx.value(layer, layer.props.prop(path).unwrap())
 }
 
@@ -523,8 +532,16 @@ fn stereo_rig_expressions_follow_the_master_camera() {
     let v3 = |s: &effectcraft_engine::Session, path: &str| {
         let comp = s.project.comp(left).unwrap();
         let layer = &comp.layers[0];
-        let ctx =
-            effectcraft_engine::render::EvalCtx { project: &s.project, comp_id: left, comp, time: Default::default(), expr: s.expr.as_deref(), footage: None };
+        let ctx = effectcraft_engine::render::EvalCtx {
+            project: &s.project,
+            comp_id: left,
+            comp,
+            time: Default::default(),
+            expr: s.expr.as_deref(),
+            footage: None,
+            property_overrides: &[],
+            media_overrides: &[],
+        };
         ctx.value(layer, layer.props.prop(path).unwrap()).as_vec3()
     };
     let close = |a: [f64; 3], b: [f64; 3]| (0..3).all(|i| (a[i] - b[i]).abs() < 1e-6);

crates/host/tests/it/main.rs

@@ -12,4 +12,5 @@ mod relink;
 mod tga_import;
 mod timeline_interop;
 mod vector_import;
+mod wav_markers;
 mod webm_metadata;

crates/host/tests/it/wav_markers.rs

@@ -0,0 +1,126 @@
+//! Markers a WAV file carries, through the fully wired session (media import included): the
+//! layer made from the file starts with them, and Update Markers From Source copies them again,
+//! through its bound `layers` parameter as well as the selection, as one undo step.
+
+use effectcraft_engine::Session;
+use effectcraft_project::LayerSource;
+use serde_json::json;
+
+/// The comments of a layer's markers, in time order.
+fn names(s: &mut Session, layer: u64) -> Vec<String> {
+    let list = s.execute_checked("markers.list", json!({"layer": layer})).unwrap();
+    list.as_array().unwrap().iter().map(|m| m["comment"].as_str().unwrap().to_string()).collect()
+}
+
+/// A one-second mono 8 kHz WAV with the named cue points `(id, sample, name)` (a `cue ` chunk and a
+/// `LIST` `adtl`).
+fn marker_wav(points: &[(u32, u32, &str)]) -> Vec<u8> {
+    fn chunk(id: &[u8; 4], body: &[u8]) -> Vec<u8> {
+        let mut v = id.to_vec();
+        v.extend((body.len() as u32).to_le_bytes());
+        v.extend(body);
+        if body.len() % 2 == 1 {
+            v.push(0);
+        }
+        v
+    }
+    let mut fmt = Vec::new();
+    fmt.extend(1u16.to_le_bytes());
+    fmt.extend(1u16.to_le_bytes());
+    fmt.extend(8000u32.to_le_bytes());
+    fmt.extend(16000u32.to_le_bytes());
+    fmt.extend(2u16.to_le_bytes());
+    fmt.extend(16u16.to_le_bytes());
+    let mut cue = (points.len() as u32).to_le_bytes().to_vec();
+    let mut adtl = b"adtl".to_vec();
+    for &(id, at, name) in points {
+        for v in [id, 0] {
+            cue.extend(v.to_le_bytes());
+        }
+        cue.extend(b"data");
+        for v in [0, 0, at] {
+            cue.extend(u32::to_le_bytes(v));
+        }
+        let mut labl = id.to_le_bytes().to_vec();
+        labl.extend(name.as_bytes());
+        labl.push(0);
+        adtl.extend(chunk(b"labl", &labl));
+    }
+    let mut body = b"WAVE".to_vec();
+    for c in [chunk(b"fmt ", &fmt), chunk(b"data", &[0; 16000]), chunk(b"cue ", &cue), chunk(b"LIST", &adtl)] {
+        body.extend(c);
+    }
+    let mut file = b"RIFF".to_vec();
+    file.extend((body.len() as u32).to_le_bytes());
+    file.extend(body);
+    file
+}
+
+/// A WAV's cue points become markers on the layer made from it, named as in the file, and
+/// Update Markers From Source brings back one that was deleted (through the fully wired session,
+/// media import included).
+#[test]
+fn a_wav_layer_starts_with_the_markers_in_its_file() {
+    let mut s = effectcraft_host::session();
+    s.execute_checked("comp.new", json!({"name": "C", "width": 64, "height": 48, "frameRate": 30, "duration": 2})).unwrap();
+    let dir = std::env::temp_dir().join(format!("effectcraft-host-wav-markers-{}", std::process::id()));
+    std::fs::create_dir_all(&dir).unwrap();
+    let path = dir.join("cues.wav");
+    std::fs::write(&path, marker_wav(&[(1, 0, "Intro"), (2, 4000, "Middle")])).unwrap();
+    let r = s.execute_checked("file.import", json!({"paths": [path.to_string_lossy()], "addToComp": true})).unwrap();
+    assert_eq!(r["errors"], json!([]), "{r}");
+    let layer = s.active_comp().unwrap().layers.iter().find(|l| matches!(l.source, LayerSource::Footage { .. })).unwrap().id.0;
+    let list = s.execute_checked("markers.list", json!({"layer": layer})).unwrap();
+    let marks: Vec<(String, f64)> =
+        list.as_array().unwrap().iter().map(|m| (m["comment"].as_str().unwrap().to_string(), m["time"].as_f64().unwrap())).collect();
+    assert_eq!(marks, [("Intro".to_string(), 0.0), ("Middle".to_string(), 0.5)]);
+    s.execute_checked("markers.delete", json!({"layer": layer, "index": 0})).unwrap();
+    assert_eq!(names(&mut s, layer), ["Middle"]);
+    s.execute_checked("layer.select", json!({"layers": [layer]})).unwrap();
+    // The bound `layers` parameter (what a script or the menu's own binding passes) brings the marker back...
+    let r = s.execute_checked("layer.updateMarkersFromSource", json!({"layers": [layer]})).unwrap();
+    assert_eq!(r["added"], 1);
+    assert_eq!(names(&mut s, layer), ["Intro", "Middle"]);
+    // ...as one undo step: undo removes it again, redo restores it.
+    assert!(s.undo());
+    assert_eq!(names(&mut s, layer), ["Middle"]);
+    assert!(s.redo());
+    assert_eq!(names(&mut s, layer), ["Intro", "Middle"]);
+    // The selection route (no parameter) finds nothing more to add.
+    assert_eq!(s.execute_checked("layer.updateMarkersFromSource", json!({})).unwrap()["added"], 0);
+    let _ = std::fs::remove_dir_all(&dir);
+}
+
+/// Reload Footage re-reads the markers the file carries: a cue point added to the file after the
+/// import is available to Update Markers From Source (and a layer already made keeps its own).
+#[test]
+fn reloading_a_wav_picks_up_cue_points_added_to_the_file() {
+    let mut s = effectcraft_host::session();
+    s.execute_checked("comp.new", json!({"name": "C", "width": 64, "height": 48, "frameRate": 30, "duration": 2})).unwrap();
+    let dir = std::env::temp_dir().join(format!("effectcraft-host-wav-reload-{}", std::process::id()));
+    std::fs::create_dir_all(&dir).unwrap();
+    let path = dir.join("cues.wav");
+    std::fs::write(&path, marker_wav(&[(1, 0, "Intro")])).unwrap();
+    let r = s.execute_checked("file.import", json!({"paths": [path.to_string_lossy()], "addToComp": true})).unwrap();
+    assert_eq!(r["errors"], json!([]), "{r}");
+    let (layer, item) = s
+        .active_comp()
+        .unwrap()
+        .layers
+        .iter()
+        .find_map(|l| match l.source {
+            LayerSource::Footage { item } => Some((l.id.0, item.0)),
+            _ => None,
+        })
+        .unwrap();
+    assert_eq!(names(&mut s, layer), ["Intro"]);
+    // The file gains a cue point; the layer does not change until asked.
+    std::fs::write(&path, marker_wav(&[(1, 0, "Intro"), (2, 4000, "Added later")])).unwrap();
+    let r = s.execute_checked("file.reloadFootage", json!({"items": [item]})).unwrap();
+    assert_eq!(r["reloaded"], 1, "{r}");
+    assert_eq!(names(&mut s, layer), ["Intro"]);
+    let r = s.execute_checked("layer.updateMarkersFromSource", json!({"layers": [layer]})).unwrap();
+    assert_eq!(r["added"], 1);
+    assert_eq!(names(&mut s, layer), ["Intro", "Added later"]);
+    let _ = std::fs::remove_dir_all(&dir);
+}

crates/media/Cargo.toml

@@ -12,6 +12,7 @@ workspace = true
 [dependencies]
 craft-docpath = { workspace = true }
 effectcraft-time = { workspace = true }
+effectcraft-color = { workspace = true }
 effectcraft-project = { workspace = true }
 effectcraft-raster = { workspace = true }
 effectcraft-render = { workspace = true }

crates/media/src/lib.rs

@@ -25,6 +25,7 @@ pub use layered::vector_doc;
 mod pool;
 mod probe;
 mod stream;
+mod wav_markers;
 mod webp_anim;
 
 pub use pool::{DEFAULT_BUDGET, MediaPool, PoolStats};

crates/media/src/probe.rs

@@ -107,8 +107,11 @@ pub fn probe_bytes(path: &str, bytes: Arc<[u8]>) -> Result<Footage> {
     let name = Path::new(path).file_name().map(|n| n.to_string_lossy().to_string()).unwrap_or_else(|| path.to_string());
     let turn = video_turn(&bytes);
     let rate = video_rate(&bytes);
+    // A WAV's cue points and XMP markers become the footage's markers.
+    let markers = crate::wav_markers::read(&bytes);
     let src = filmcraft_codecs::open_bytes(&name, bytes)?;
     let mut f = footage_from_info(path, src.info());
+    f.markers = markers;
     turn_footage(&mut f, turn);
     correct_rate(&mut f, rate);
     Ok(f)

crates/media/src/wav_markers.rs

@@ -0,0 +1,517 @@
+//! Markers a WAV file carries, read from its RIFF chunks.
+//!
+//! Two encodings are read and merged:
+//! - **Cue points** (the standard): a `cue ` chunk with one point per marker, named by `labl` (or
+//!   `note`) sub-chunks of a `LIST` `adtl` chunk, and given a length by `ltxt`.
+//! - **XMP** (Adobe's tools): an `_PMX` chunk holding an XMP packet whose `xmpDM:markers` list has
+//!   one entry per marker (`xmpDM:startTime`, `xmpDM:duration`, `xmpDM:name`), counted in frames
+//!   of `xmpDM:frameRate` (`f44100` for samples at 44.1 kHz).
+//!
+//! RF64 files (WAVs over 4 GB) carry a `0xFFFFFFFF` size for a chunk too big for 32 bits and give its real size in a
+//! `ds64` chunk; those sizes are resolved so the chunks after the audio are still found.
+//!
+//! The file is untrusted input: every read is bounds-checked, sizes use checked arithmetic, and
+//! the number of markers, of `adtl` sub-chunks looked at and the size of the XMP packet are capped.
+
+use std::collections::{HashMap, HashSet};
+
+use effectcraft_color::Label;
+use effectcraft_project::Marker;
+use effectcraft_time::Tick;
+
+/// Most markers read from one file.
+pub const MAX_MARKERS: usize = 10_000;
+/// Largest XMP packet read (bytes).
+const MAX_XMP: usize = 4 << 20;
+/// Most `adtl` sub-chunks (`labl`, `note`, `ltxt`) looked at in one file: a few per cue point is plenty.
+const MAX_ADTL_RECORDS: usize = 4 * MAX_MARKERS;
+/// Most entries read from an RF64 file's `ds64` size table.
+const MAX_DS64_TABLE: usize = 1_024;
+
+fn u32_at(b: &[u8], at: usize) -> Option<u32> {
+    let s = b.get(at..at.checked_add(4)?)?;
+    Some(u32::from_le_bytes(s.try_into().ok()?))
+}
+
+fn u64_at(b: &[u8], at: usize) -> Option<u64> {
+    let s = b.get(at..at.checked_add(8)?)?;
+    Some(u64::from_le_bytes(s.try_into().ok()?))
+}
+
+/// The text of a NUL-terminated label (the rest of the chunk), lossily decoded.
+fn label(b: &[u8]) -> String {
+    let end = b.iter().position(|&c| c == 0).unwrap_or(b.len());
+    String::from_utf8_lossy(b.get(..end).unwrap_or_default()).trim().to_string()
+}
+
+fn secs(frames: f64, rate: f64) -> Tick {
+    if rate > 0.0 && frames.is_finite() { Tick::from_seconds_f64((frames / rate).max(0.0)) } else { Tick::ZERO }
+}
+
+/// Whether `bytes` start a RIFF/WAVE file.
+pub fn is_wav(bytes: &[u8]) -> bool {
+    matches!(bytes.get(0..4), Some(b"RIFF" | b"RF64")) && bytes.get(8..12) == Some(b"WAVE")
+}
+
+/// The sizes an RF64 file's `ds64` chunk gives for chunks too big for the 32-bit size field.
+struct Ds64 {
+    /// The `data` chunk's size.
+    data: u64,
+    /// Other chunks: `(id, size)`.
+    table: Vec<([u8; 4], u64)>,
+}
+
+impl Ds64 {
+    /// The real size of chunk `id`, when the file says.
+    fn size_of(&self, id: &[u8; 4]) -> Option<u64> {
+        if id == b"data" { Some(self.data) } else { self.table.iter().find(|(t, _)| t == id).map(|(_, size)| *size) }
+    }
+}
+
+/// The `ds64` chunk of an RF64 file (`RF64`, size, `WAVE`, then `ds64`); `None` for any other file or one whose
+/// `ds64` doesn't fit.
+fn ds64(bytes: &[u8]) -> Option<Ds64> {
+    if bytes.get(0..4) != Some(b"RF64") || bytes.get(12..16) != Some(b"ds64") {
+        return None;
+    }
+    let size = usize::try_from(u32_at(bytes, 16)?).ok()?;
+    let body = bytes.get(20..20usize.checked_add(size)?)?;
+    // riff size (8), data size (8), sample count (8), table length (4), then `(id, size)` entries of 12 bytes
+    let data = u64_at(body, 8)?;
+    let entries = usize::try_from(u32_at(body, 24)?).ok()?;
+    let mut table = Vec::new();
+    for i in 0..entries.min(MAX_DS64_TABLE) {
+        let at = 28usize.checked_add(i.checked_mul(12)?)?;
+        let id = <[u8; 4]>::try_from(body.get(at..at.checked_add(4)?)?).ok()?;
+        table.push((id, u64_at(body, at + 4)?));
+    }
+    Some(Ds64 { data, table })
+}
+
+/// The chunks of a WAVE file as `(id, body)`, stopping at the first one that doesn't fit.
+fn chunks(bytes: &[u8]) -> Vec<([u8; 4], &[u8])> {
+    let big = ds64(bytes);
+    let mut out = Vec::new();
+    let mut at = 12usize;
+    while let Some(head) = bytes.get(at..at.saturating_add(8)) {
+        let (Ok(id), Some(field)) = (<[u8; 4]>::try_from(&head[..4]), u32_at(head, 4)) else { break };
+        // In an RF64 file a size field of 0xFFFFFFFF stands for the size `ds64` gives.
+        let size = match &big {
+            Some(d) if field == u32::MAX => d.size_of(&id).unwrap_or(u64::from(field)),
+            _ => u64::from(field),
+        };
+        let start = at.saturating_add(8);
+        let Some(end) = usize::try_from(size).ok().and_then(|n| start.checked_add(n)) else { break };
+        let Some(body) = bytes.get(start..end) else { break };
+        out.push((id, body));
+        // Chunks are padded to an even size.
+        at = end.saturating_add(end & 1);
+    }
+    out
+}
+
+/// The markers `bytes` carry, in time order (empty for anything that isn't a WAV with markers).
+pub fn read(bytes: &[u8]) -> Vec<Marker> {
+    if !is_wav(bytes) {
+        return Vec::new();
+    }
+    let chunks = chunks(bytes);
+    let rate = chunks.iter().find(|(id, _)| id == b"fmt ").and_then(|(_, b)| u32_at(b, 4)).map_or(0.0, f64::from);
+    let mut out = cue_markers(&chunks, rate);
+    if let Some((_, xmp)) = chunks.iter().find(|(id, _)| id == b"_PMX") {
+        // Tools that write both encodings repeat each marker.
+        let mut seen: HashSet<(String, Tick)> = out.iter().map(|o| (o.comment.clone(), o.time)).collect();
+        for m in xmp_markers(xmp, rate) {
+            if seen.insert((m.comment.clone(), m.time)) {
+                out.push(m);
+            }
+        }
+    }
+    out.truncate(MAX_MARKERS);
+    out.sort_by_key(|m| m.time);
+    out
+}
+
+/// Cue points named and sized by the `adtl` list.
+fn cue_markers(chunks: &[([u8; 4], &[u8])], rate: f64) -> Vec<Marker> {
+    let Some((_, cue)) = chunks.iter().find(|(id, _)| id == b"cue ") else { return Vec::new() };
+    let count = (u32_at(cue, 0).unwrap_or(0) as usize).min(MAX_MARKERS);
+    // The cue points first: `(id, offset in samples)`.
+    let mut points = Vec::new();
+    for i in 0..count {
+        let Some(point) = cue.get(4usize.saturating_add(i.saturating_mul(24))..) else { break };
+        let (Some(id), Some(offset)) = (u32_at(point, 0), u32_at(point, 20)) else { break };
+        points.push((id, offset));
+    }
+    // Only the names and lengths of those ids are kept, so a hostile `adtl` list cannot grow them past the cue count,
+    // and each record is a lookup, not a scan.
+    let wanted: HashSet<u32> = points.iter().map(|(id, _)| *id).collect();
+    let mut names: HashMap<u32, String> = HashMap::new();
+    let mut lengths: HashMap<u32, u32> = HashMap::new();
+    let mut records = 0usize;
+    'lists: for (_, list) in chunks.iter().filter(|(id, b)| id == b"LIST" && b.get(0..4) == Some(b"adtl")) {
+        let mut at = 4usize;
+        while let Some(head) = list.get(at..at.saturating_add(8)) {
+            let (Ok(id), Some(size)) = (<[u8; 4]>::try_from(&head[..4]), u32_at(head, 4)) else { break };
+            let start = at.saturating_add(8);
+            let Some(end) = start.checked_add(size as usize) else { break };
+            let Some(body) = list.get(start..end) else { break };
+            records += 1;
+            if records > MAX_ADTL_RECORDS {
+                break 'lists;
+            }
+            if let Some(cue_id) = u32_at(body, 0).filter(|c| wanted.contains(c)) {
+                match &id {
+                    // A `labl` is the name; a `note` only when there is none.
+                    b"labl" => {
+                        names.insert(cue_id, label(body.get(4..).unwrap_or_default()));
+                    }
+                    b"note" => {
+                        names.entry(cue_id).or_insert_with(|| label(body.get(4..).unwrap_or_default()));
+                    }
+                    // The first `ltxt` of a cue point gives its length.
+                    b"ltxt" => {
+                        lengths.entry(cue_id).or_insert_with(|| u32_at(body, 4).unwrap_or(0));
+                    }
+                    _ => {}
+                }
+            }
+            at = end.saturating_add(end & 1);
+        }
+    }
+    points
+        .into_iter()
+        .map(|(id, offset)| {
+            let comment = names.get(&id).cloned().unwrap_or_default();
+            let length = lengths.get(&id).copied().unwrap_or(0);
+            Marker { time: secs(f64::from(offset), rate), duration: secs(f64::from(length), rate), comment, label: Label::None, ..Default::default() }
+        })
+        .collect()
+}
+
+/// The text of `name` in an XMP entry, as an attribute (`name="v"`) or an element
+/// (`<name>v</name>`).
+fn xmp_value(entry: &str, name: &str) -> Option<String> {
+    let attr = format!("{name}=\"");
+    if let Some(i) = entry.find(&attr) {
+        let rest = entry.get(i + attr.len()..)?;
+        return Some(unescape(rest.get(..rest.find('"')?)?));
+    }
+    let open = format!("<{name}>");
+    let i = entry.find(&open)?;
+    let rest = entry.get(i + open.len()..)?;
+    Some(unescape(rest.get(..rest.find('<')?)?))
+}
+
+fn unescape(s: &str) -> String {
+    let mut out = String::with_capacity(s.len());
+    let mut rest = s;
+    while let Some(i) = rest.find('&') {
+        out.push_str(rest.get(..i).unwrap_or_default());
+        let tail = rest.get(i..).unwrap_or_default();
+        let Some(semi) = tail.find(';').filter(|&n| n <= 10) else {
+            out.push('&');
+            rest = tail.get(1..).unwrap_or_default();
+            continue;
+        };
+        let ent = tail.get(1..semi).unwrap_or_default();
+        match ent {
+            "amp" => out.push('&'),
+            "lt" => out.push('<'),
+            "gt" => out.push('>'),
+            "quot" => out.push('"'),
+            "apos" => out.push('\''),
+            _ => {
+                let code = ent.strip_prefix("#x").and_then(|h| u32::from_str_radix(h, 16).ok()).or_else(|| ent.strip_prefix('#').and_then(|d| d.parse().ok()));
+                match code.and_then(char::from_u32) {
+                    Some(c) => out.push(c),
+                    None => out.push_str(tail.get(..=semi).unwrap_or_default()),
+                }
+            }
+        }
+        rest = tail.get(semi + 1..).unwrap_or_default();
+    }
+    out.push_str(rest);
+    out.trim().to_string()
+}
+
+/// A frame rate as XMP writes it: `f44100`, or `f30000s1001` (rate over scale).
+fn xmp_rate(text: &str) -> Option<f64> {
+    let t = text.trim().strip_prefix('f')?;
+    let (num, den) = t.split_once('s').unwrap_or((t, "1"));
+    let (n, d): (f64, f64) = (num.parse().ok()?, den.parse().ok()?);
+    (n > 0.0 && d > 0.0).then_some(n / d)
+}
+
+/// The markers of an XMP packet's `xmpDM:markers` entries.
+fn xmp_markers(packet: &[u8], file_rate: f64) -> Vec<Marker> {
+    let text = String::from_utf8_lossy(packet.get(..packet.len().min(MAX_XMP)).unwrap_or_default());
+    let mut out = Vec::new();
+    // The frame rate belongs to the track an entry follows.
+    let mut rate = file_rate;
+    for entry in text.split("<rdf:li").skip(1) {
+        if let Some(r) = xmp_value(entry, "xmpDM:frameRate").as_deref().and_then(xmp_rate) {
+            rate = r;
+        }
+        let Some(start) = xmp_value(entry, "xmpDM:startTime").and_then(|v| v.trim().parse::<f64>().ok()) else { continue };
+        let length = xmp_value(entry, "xmpDM:duration").and_then(|v| v.trim().parse::<f64>().ok()).unwrap_or(0.0);
+        let comment = xmp_value(entry, "xmpDM:name").unwrap_or_default();
+        out.push(Marker { time: secs(start, rate), duration: secs(length, rate), comment, label: Label::None, ..Default::default() });
+        if out.len() >= MAX_MARKERS {
+            break;
+        }
+    }
+    out
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn chunk(id: &[u8; 4], body: &[u8]) -> Vec<u8> {
+        let mut v = id.to_vec();
+        v.extend((body.len() as u32).to_le_bytes());
+        v.extend(body);
+        if body.len() % 2 == 1 {
+            v.push(0);
+        }
+        v
+    }
+
+    fn fmt(rate: u32) -> Vec<u8> {
+        let mut b = Vec::new();
+        b.extend(1u16.to_le_bytes()); // PCM
+        b.extend(1u16.to_le_bytes()); // mono
+        b.extend(rate.to_le_bytes());
+        b.extend((rate * 2).to_le_bytes());
+        b.extend(2u16.to_le_bytes());
+        b.extend(16u16.to_le_bytes());
+        chunk(b"fmt ", &b)
+    }
+
+    fn wav(chunks: &[Vec<u8>]) -> Vec<u8> {
+        let body: Vec<u8> = chunks.iter().flatten().copied().collect();
+        let mut v = b"RIFF".to_vec();
+        v.extend((body.len() as u32 + 4).to_le_bytes());
+        v.extend(b"WAVE");
+        v.extend(body);
+        v
+    }
+
+    fn cue(points: &[(u32, u32)]) -> Vec<u8> {
+        let mut b = (points.len() as u32).to_le_bytes().to_vec();
+        for (id, offset) in points {
+            b.extend(id.to_le_bytes());
+            b.extend(0u32.to_le_bytes());
+            b.extend(b"data");
+            b.extend(0u32.to_le_bytes());
+            b.extend(0u32.to_le_bytes());
+            b.extend(offset.to_le_bytes());
+        }
+        chunk(b"cue ", &b)
+    }
+
+    fn labl(id: &[u8; 4], cue_id: u32, text: &str) -> Vec<u8> {
+        let mut b = cue_id.to_le_bytes().to_vec();
+        b.extend(text.as_bytes());
+        b.push(0);
+        chunk(id, &b)
+    }
+
+    fn adtl(subs: &[Vec<u8>]) -> Vec<u8> {
+        let mut b = b"adtl".to_vec();
+        b.extend(subs.iter().flatten());
+        chunk(b"LIST", &b)
+    }
+
+    #[test]
+    fn cue_points_are_named_by_the_adtl_list_and_timed_in_samples() {
+        let file = wav(&[
+            fmt(44100),
+            chunk(b"data", &[0; 8]),
+            cue(&[(2, 88200), (1, 22050)]),
+            adtl(&[labl(b"labl", 1, "SEQ01_Prologue"), labl(b"labl", 2, "SEQ02_Vallee_P1_Agriculture")]),
+        ]);
+        let m = read(&file);
+        assert_eq!(m.len(), 2);
+        assert_eq!((m[0].comment.as_str(), m[0].time), ("SEQ01_Prologue", Tick::from_seconds_f64(0.5)));
+        assert_eq!((m[1].comment.as_str(), m[1].time), ("SEQ02_Vallee_P1_Agriculture", Tick::from_seconds_f64(2.0)));
+    }
+
+    #[test]
+    fn a_note_names_a_cue_only_when_it_has_no_label_and_ltxt_gives_a_length() {
+        let mut ltxt = 1u32.to_le_bytes().to_vec();
+        ltxt.extend(44100u32.to_le_bytes());
+        ltxt.extend([0; 16]);
+        let file = wav(&[
+            fmt(44100),
+            cue(&[(1, 0), (2, 44100)]),
+            adtl(&[labl(b"note", 1, "from note"), chunk(b"ltxt", &ltxt), labl(b"labl", 2, "named"), labl(b"note", 2, "ignored")]),
+        ]);
+        let m = read(&file);
+        assert_eq!((m[0].comment.as_str(), m[0].duration), ("from note", Tick::from_seconds_f64(1.0)));
+        assert_eq!(m[1].comment, "named");
+    }
+
+    const XMP_ELEMENTS: &str = r#"<x:xmpmeta><rdf:RDF><rdf:Description><xmpDM:Tracks><rdf:Bag><rdf:li rdf:parseType="Resource"><xmpDM:trackName>Markers</xmpDM:trackName><xmpDM:trackType>Cue</xmpDM:trackType><xmpDM:frameRate>f44100</xmpDM:frameRate><xmpDM:markers><rdf:Seq><rdf:li rdf:parseType="Resource"><xmpDM:startTime>44100</xmpDM:startTime><xmpDM:duration>0</xmpDM:duration><xmpDM:name>One &amp; Two</xmpDM:name></rdf:li><rdf:li rdf:parseType="Resource"><xmpDM:startTime>132300</xmpDM:startTime><xmpDM:duration>22050</xmpDM:duration><xmpDM:name>Three</xmpDM:name></rdf:li></rdf:Seq></xmpDM:markers></rdf:li></rdf:Bag></xmpDM:Tracks></rdf:Description></rdf:RDF></x:xmpmeta>"#;
+
+    #[test]
+    fn xmp_markers_are_read_as_elements_in_frames_of_the_track_rate() {
+        let file = wav(&[fmt(48000), chunk(b"_PMX", XMP_ELEMENTS.as_bytes())]);
+        let m = read(&file);
+        assert_eq!(m.len(), 2);
+        // 44100 frames at f44100 is one second, whatever the file's own rate.
+        assert_eq!((m[0].comment.as_str(), m[0].time), ("One & Two", Tick::from_seconds_f64(1.0)));
+        assert_eq!((m[1].comment.as_str(), m[1].time, m[1].duration), ("Three", Tick::from_seconds_f64(3.0), Tick::from_seconds_f64(0.5)));
+    }
+
+    #[test]
+    fn xmp_markers_are_read_as_attributes_and_use_the_file_rate_without_a_track_rate() {
+        let xmp = r#"<rdf:Seq><rdf:li xmpDM:startTime="24000" xmpDM:duration="0" xmpDM:name="Attr &#233;"/></rdf:Seq>"#;
+        let m = read(&wav(&[fmt(48000), chunk(b"_PMX", xmp.as_bytes())]));
+        assert_eq!((m[0].comment.as_str(), m[0].time), ("Attr é", Tick::from_seconds_f64(0.5)));
+    }
+
+    #[test]
+    fn a_marker_in_both_encodings_is_listed_once() {
+        let xmp = r#"<rdf:li xmpDM:startTime="44100" xmpDM:name="Same"/><rdf:li xmpDM:startTime="88200" xmpDM:name="Only XMP"/>"#;
+        let file = wav(&[fmt(44100), cue(&[(1, 44100)]), adtl(&[labl(b"labl", 1, "Same")]), chunk(b"_PMX", xmp.as_bytes())]);
+        let names: Vec<String> = read(&file).into_iter().map(|m| m.comment).collect();
+        assert_eq!(names, ["Same", "Only XMP"]);
+    }
+
+    #[test]
+    fn importing_a_wav_puts_its_markers_on_the_footage() {
+        let file = wav(&[
+            fmt(44100),
+            chunk(b"data", &[0; 4 * 44100]),
+            cue(&[(1, 0), (2, 44100)]),
+            adtl(&[labl(b"labl", 1, "SEQ01_Prologue"), labl(b"labl", 2, "SEQ02_Vallee_P1_Agriculture")]),
+        ]);
+        let f = crate::probe::probe_bytes("markers.wav", file.into()).expect("probe");
+        assert!(f.has_audio);
+        let names: Vec<&str> = f.markers.iter().map(|m| m.comment.as_str()).collect();
+        assert_eq!(names, ["SEQ01_Prologue", "SEQ02_Vallee_P1_Agriculture"]);
+        assert_eq!(f.markers[1].time, Tick::from_seconds_f64(1.0));
+    }
+
+    #[test]
+    fn damaged_or_hostile_files_read_as_far_as_they_go_without_panicking() {
+        assert!(read(b"").is_empty());
+        assert!(read(b"RIFF").is_empty());
+        assert!(read(b"not a wav file at all").is_empty());
+        let good = wav(&[fmt(44100), cue(&[(1, 44100)]), adtl(&[labl(b"labl", 1, "Kept")])]);
+        // Every truncation is safe.
+        for n in 0..good.len() {
+            let _ = read(&good[..n]);
+        }
+        // A cue count far beyond the chunk, and chunk sizes past the end of the file.
+        let mut huge = 0xFFFF_FFFFu32.to_le_bytes().to_vec();
+        huge.extend([0; 24]);
+        let m = read(&wav(&[fmt(44100), chunk(b"cue ", &huge)]));
+        assert!(m.len() <= 1);
+        let mut lying = good.clone();
+        lying.extend(b"LIST\xff\xff\xff\xffadtl");
+        assert_eq!(read(&lying).len(), 1);
+        // No sample rate: times are zero, not a division by zero.
+        let m = read(&wav(&[cue(&[(1, 44100)])]));
+        assert_eq!(m[0].time, Tick::ZERO);
+    }
+
+    /// A chunk whose size field says `field` (an RF64 file's `0xFFFFFFFF`) while its body is `body`.
+    fn chunk_with_size_field(id: &[u8; 4], field: u32, body: &[u8]) -> Vec<u8> {
+        let mut v = id.to_vec();
+        v.extend(field.to_le_bytes());
+        v.extend(body);
+        if body.len() % 2 == 1 {
+            v.push(0);
+        }
+        v
+    }
+
+    /// An RF64 `ds64` chunk: the `data` chunk's size and a table of other chunks' sizes.
+    fn ds64_chunk(data_size: u64, table: &[([u8; 4], u64)]) -> Vec<u8> {
+        let mut b = 0u64.to_le_bytes().to_vec(); // riff size (not used)
+        b.extend(data_size.to_le_bytes());
+        b.extend(0u64.to_le_bytes()); // sample count
+        b.extend((table.len() as u32).to_le_bytes());
+        for (id, size) in table {
+            b.extend(id);
+            b.extend(size.to_le_bytes());
+        }
+        chunk(b"ds64", &b)
+    }
+
+    fn rf64(chunks: &[Vec<u8>]) -> Vec<u8> {
+        let body: Vec<u8> = chunks.iter().flatten().copied().collect();
+        let mut v = b"RF64".to_vec();
+        v.extend(u32::MAX.to_le_bytes());
+        v.extend(b"WAVE");
+        v.extend(body);
+        v
+    }
+
+    #[test]
+    fn rf64_markers_after_a_data_chunk_of_sentinel_size_are_read() {
+        let audio = [0u8; 8];
+        let file = rf64(&[
+            ds64_chunk(audio.len() as u64, &[]),
+            fmt(44100),
+            chunk_with_size_field(b"data", u32::MAX, &audio),
+            cue(&[(1, 44100)]),
+            adtl(&[labl(b"labl", 1, "After the audio")]),
+        ]);
+        let m = read(&file);
+        assert_eq!(m.len(), 1);
+        assert_eq!((m[0].comment.as_str(), m[0].time), ("After the audio", Tick::from_seconds_f64(1.0)));
+    }
+
+    #[test]
+    fn rf64_sizes_of_other_chunks_come_from_the_ds64_table() {
+        let junk = [7u8; 6];
+        let tail = || [cue(&[(1, 8000)]), adtl(&[labl(b"labl", 1, "Found")])].concat();
+        let with_entry = rf64(&[ds64_chunk(0, &[(*b"junk", junk.len() as u64)]), fmt(8000), chunk_with_size_field(b"junk", u32::MAX, &junk), tail()]);
+        assert_eq!(read(&with_entry)[0].comment, "Found");
+        // Without the table entry the sentinel is all there is, and what follows is not reached.
+        let without = rf64(&[ds64_chunk(0, &[]), fmt(8000), chunk_with_size_field(b"junk", u32::MAX, &junk), tail()]);
+        assert!(read(&without).is_empty());
+    }
+
+    #[test]
+    fn hostile_rf64_size_tables_read_as_far_as_they_go_without_panicking() {
+        // sizes that overflow when added to an offset
+        for data in [u64::MAX, u64::MAX - 7, 1 << 63] {
+            let file = rf64(&[ds64_chunk(data, &[(*b"junk", u64::MAX)]), fmt(8000), chunk_with_size_field(b"data", u32::MAX, &[0; 4]), cue(&[(1, 0)])]);
+            assert!(read(&file).is_empty());
+        }
+        // a table that claims far more entries than its chunk holds
+        let mut liar = ds64_chunk(0, &[]);
+        liar[8 + 24..8 + 28].copy_from_slice(&u32::MAX.to_le_bytes());
+        let _ = read(&rf64(&[liar, fmt(8000), cue(&[(1, 0)])]));
+        // every truncation of a good RF64 file is safe
+        let good =
+            rf64(&[ds64_chunk(4, &[]), fmt(44100), chunk_with_size_field(b"data", u32::MAX, &[0; 4]), cue(&[(1, 44100)]), adtl(&[labl(b"labl", 1, "Kept")])]);
+        assert_eq!(read(&good).len(), 1);
+        for n in 0..good.len() {
+            let _ = read(&good[..n]);
+        }
+    }
+
+    #[test]
+    fn a_huge_adtl_list_is_read_in_linear_time_and_only_for_the_cue_points_that_exist() {
+        // Records for ids that have no cue point are skipped, not stored, and the number looked at is capped.
+        let junk = |n: u32| (1000..1000 + n).map(|id| labl(b"labl", id, "n")).collect::<Vec<_>>();
+        let started = std::time::Instant::now();
+        // the real label comes first: read
+        let mut subs = vec![labl(b"labl", 1, "Real")];
+        subs.extend(junk(100_000));
+        let m = read(&wav(&[fmt(44100), cue(&[(1, 44100)]), adtl(&subs)]));
+        assert_eq!(m[0].comment, "Real");
+        // it comes after more records than are looked at: not read, and the marker is still there
+        let mut subs = junk(MAX_ADTL_RECORDS as u32 + 10);
+        subs.push(labl(b"labl", 1, "Too late"));
+        let m = read(&wav(&[fmt(44100), cue(&[(1, 44100)]), adtl(&subs)]));
+        assert_eq!((m.len(), m[0].comment.as_str()), (1, ""));
+        assert!(started.elapsed() < std::time::Duration::from_secs(5), "took {:?}", started.elapsed());
+    }
+}

crates/project/src/build.rs

@@ -881,6 +881,14 @@ pub fn layer(project: &mut Project, comp: &Comp, name: &str, source: LayerSource
             _ => {}
         }
     }
+    // A footage layer starts with the markers its file carries (layer time is footage time).
+    let footage_markers = match &source {
+        LayerSource::Footage { item } => match project.item(*item).map(|i| &i.kind) {
+            Some(crate::ItemKind::Footage(f)) => f.markers.clone(),
+            _ => vec![],
+        },
+        _ => vec![],
+    };
     let has_audio = matches!(&source, LayerSource::Footage { item } if matches!(project.item(*item).map(|i| &i.kind), Some(crate::ItemKind::Footage(f)) if f.has_audio))
         || matches!(source, LayerSource::Comp { .. });
     if has_audio {
@@ -910,7 +918,7 @@ pub fn layer(project: &mut Project, comp: &Comp, name: &str, source: LayerSource
         preserve_transparency: false,
         track_matte: None,
         parent: None,
-        markers: vec![],
+        markers: footage_markers,
         markers_locked: false,
         environment: false,
         environment_background: false,

crates/project/src/footage.rs

@@ -1,4 +1,4 @@
-use super::settings::yes;
+use super::settings::{Marker, yes};
 use super::{ColorSpace, Deserialize, FrameRate, Serialize, Tick};
 
 #[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Serialize, Deserialize)]
@@ -115,6 +115,10 @@ pub struct Footage {
     /// timecode isn't read). It only relabels source time, as in After Effects.
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub start_timecode: Option<i64>,
+    /// Markers the file carries (a WAV's cue points and XMP markers), at footage time. A layer
+    /// made from the footage starts with them, and Update Markers From Source copies new ones.
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub markers: Vec<Marker>,
 }
 
 fn is_default<T: Default + PartialEq>(v: &T) -> bool {
@@ -150,6 +154,7 @@ impl Default for Footage {
             page: 0,
             alphabetical: false,
             start_timecode: None,
+            markers: vec![],
         }
     }
 }

crates/project/src/render_queue.rs

@@ -442,9 +442,18 @@ impl RenderSettings {
     pub fn frame_time(&self, comp: &Comp, i: u64) -> Tick {
         self.rate(comp).tick_of(self.first_frame(comp) + i as i64)
     }
-    pub fn output_size(&self, comp: &Comp) -> (u32, u32) {
+    pub fn effective_scale(&self, comp: &Comp) -> f64 {
         let s = self.resolution.clamp(0.01, 4.0);
-        (((comp.width as f64 * s).round() as u32).max(1), ((comp.height as f64 * s).round() as u32).max(1))
+        let max = f64::from(crate::limits::MAX_SIZE);
+        s.min(max / f64::from(comp.width.max(1))).min(max / f64::from(comp.height.max(1)))
+    }
+    pub fn output_size(&self, comp: &Comp) -> (u32, u32) {
+        let s = self.effective_scale(comp);
+        // The scale is clamped so neither side exceeds the comp limit, keeping the aspect
+        // ratio: a 30 000 px side at 4x renders at 1x instead of cropping to a corner.
+        let w = ((comp.width as f64 * s).round() as u32).max(1);
+        let h = ((comp.height as f64 * s).round() as u32).max(1);
+        (w, h)
     }
     pub fn resolution_label(&self) -> &'static str {
         match self.resolution {
@@ -779,15 +788,18 @@ impl Crop {
         if self.use_roi
             && let Some([x, y, rw, rh]) = self.roi
         {
-            // The quad arrives unvalidated (control channel or a hand-edited project):
-            // clamp like the sibling edge fields (plus/minus 20 000) and subtract
-            // without overflow.
-            let conv = |v: f64| v.round().clamp(-20_000.0, 20_000.0) as i32;
-            let l = conv(x * scale);
-            let t = conv(y * scale);
-            let r = (w as i32).saturating_sub(conv((x + rw) * scale));
-            let b = (h as i32).saturating_sub(conv((y + rh) * scale));
-            return (t, l, b, r);
+            // The quad arrives unvalidated (control channel or a hand-edited project). As in
+            // After Effects, the region of interest lies inside the frame: each converted edge
+            // is clamped to [0, w] / [0, h] (inf clamps to a side, NaN converts to 0), and the
+            // far edge never passes the near one. Every edge then lies inside the frame, so the
+            // crop can't be larger than the frame and no subtraction can overflow.
+            let (wi, hi) = (i32::try_from(w).unwrap_or(i32::MAX), i32::try_from(h).unwrap_or(i32::MAX));
+            let conv = |v: f64, side: i32| v.round().clamp(0.0, f64::from(side)) as i32;
+            let l = conv(x * scale, wi);
+            let t = conv(y * scale, hi);
+            let r = conv((x + rw) * scale, wi).max(l);
+            let b = conv((y + rh) * scale, hi).max(t);
+            return (t, l, hi - b, wi - r);
         }
         (self.top, self.left, self.bottom, self.right)
     }
@@ -1126,7 +1138,7 @@ impl OutputModule {
     /// rounding).
     pub fn output_size(&self, comp: &Comp, settings: &RenderSettings) -> (u32, u32) {
         let (w, h) = settings.output_size(comp);
-        let (w, h) = self.frame_size(w, h, settings.resolution.clamp(0.01, 4.0));
+        let (w, h) = self.frame_size(w, h, settings.effective_scale(comp));
         self.format.coded_size(w, h)
     }
     /// Every setting as `(label, value)` lines (render logs).
@@ -1659,8 +1671,8 @@ mod tests {
 
     #[test]
     fn hostile_roi_cannot_overflow_crop_math() {
-        // `-1e12` saturates to `i32::MIN` on conversion: `w as i32 - l` must saturate,
-        // not overflow, and still yield a usable (degenerate) frame size.
+        // `-1e12` is clamped into the frame on conversion: it must not overflow and must still
+        // yield a usable (degenerate) frame size.
         let c = Comp::new(1920, 1080, FrameRate::new(30, 1), Tick::from_seconds_f64(1.0));
         let rs = RenderSettings::default();
         let mut m = OutputModule::for_format(OutputFormat::PngSequence);
@@ -1673,6 +1685,66 @@ mod tests {
         assert_eq!(m.output_size(&c, &half), (400, 200));
     }
 
+    #[test]
+    fn output_size_never_exceeds_the_comp_limit() {
+        // The effective scale is clamped so neither side exceeds the limit (exporter
+        // `w * h * 4` would overflow at 120 000 px sides); the pipeline renders at the
+        // same scale, so it never requests a frame larger than this reports.
+        let rs = RenderSettings { resolution: 4.0, ..Default::default() };
+        let m = OutputModule::for_format(OutputFormat::PngSequence);
+        let square = Comp::new(30_000, 30_000, FrameRate::new(30, 1), Tick::from_seconds_f64(1.0));
+        assert_eq!(rs.effective_scale(&square), 1.0);
+        assert_eq!(rs.output_size(&square), (30_000, 30_000));
+        assert_eq!(m.output_size(&square, &rs), (30_000, 30_000));
+        // Wide comps keep their aspect ratio instead of clamping each side on its own.
+        let wide = Comp::new(30_000, 15_000, FrameRate::new(30, 1), Tick::from_seconds_f64(1.0));
+        assert_eq!(rs.effective_scale(&wide), 1.0);
+        assert_eq!(rs.output_size(&wide), (30_000, 15_000));
+        assert_eq!(m.output_size(&wide, &rs), (30_000, 15_000));
+        // A mid-size comp renders at the largest scale that still fits.
+        let mid = Comp::new(20_000, 10_000, FrameRate::new(30, 1), Tick::from_seconds_f64(1.0));
+        assert_eq!(mid.width as f64 * rs.effective_scale(&mid), 30_000.0);
+        assert_eq!(rs.output_size(&mid), (30_000, 15_000));
+    }
+
+    #[test]
+    fn valid_wide_roi_endpoints_are_preserved() {
+        // A supported 30 000 x 100 frame at scale 1: ROI [10000, 0, 20000, 100] spans x 10 000..30 000
+        // and must give 20 000 x 100 (the absolute right edge 30 000 exceeds the old +/-20 000 clamp).
+        let c = Comp::new(30_000, 100, FrameRate::new(30, 1), Tick::from_seconds_f64(1.0));
+        let rs = RenderSettings::default();
+        let mut m = OutputModule::for_format(OutputFormat::PngSequence);
+        m.crop = Crop { enabled: true, use_roi: true, roi: Some([10_000.0, 0.0, 20_000.0, 100.0]), ..Default::default() };
+        assert_eq!(m.output_size(&c, &rs), (20_000, 100));
+        assert_eq!(m.crop.edges(30_000, 100, 1.0), (0, 10_000, 0, 0));
+        // Scale 4.0 pushes a valid edge to 120 000 px (30 000 x 4); the left edge 40 000 and the
+        // right edge 120 000 are both beyond 20 000 and must survive.
+        assert_eq!(m.crop.edges(120_000, 400, 4.0), (0, 40_000, 0, 0));
+        assert_eq!(m.frame_size(120_000, 400, 4.0), (80_000, 400));
+        // Hostile quads stay inside the frame: never empty, never larger than the frame, so the
+        // export can't be asked for an unbounded crop (an ROI reaching far outside the comp
+        // used to pad the frame instead).
+        let (fw, fh) = (1920, 1080);
+        let hostile = [
+            [1e300, 1e300, 1e300, 1e300],
+            [-1e300, -1e300, 1e300, 1e300],
+            [-1e6, -1e6, 2e6 + 1920.0, 2e6 + 1080.0],
+            [-1e12, -1e12, -1e12, -1e12],
+            [f64::NAN, f64::INFINITY, f64::NEG_INFINITY, f64::NAN],
+            [f64::NEG_INFINITY, f64::NEG_INFINITY, f64::INFINITY, f64::INFINITY],
+        ];
+        for roi in hostile {
+            m.crop.roi = Some(roi);
+            let (t, l, b, r) = m.crop.edges(fw, fh, 1.0);
+            assert!([t, l, b, r].iter().all(|e| *e >= 0), "{roi:?}: an edge pads the frame: {:?}", (t, l, b, r));
+            let (w, h) = m.frame_size(fw, fh, 1.0);
+            assert!((1..=fw).contains(&w) && (1..=fh).contains(&h), "{roi:?}: {w}x{h} is outside 1x1..={fw}x{fh}");
+        }
+        // An ROI covering more than the frame is the whole frame.
+        m.crop.roi = Some([-1e6, -1e6, 2e6 + 1920.0, 2e6 + 1080.0]);
+        assert_eq!(m.frame_size(fw, fh, 1.0), (fw, fh));
+    }
+
     #[test]
     fn uncompressed_quicktime_format() {
         let f = OutputFormat::from_name("uncompressed").unwrap();

crates/raster/src/lib.rs

@@ -23,6 +23,11 @@ pub use warp::{Sampling, WarpOpts, accumulate_warp, composite_warp, composite_wa
 
 pub type Px = [f32; 4];
 
+/// Maximum padded side in pixels — mirrors the project crate's `limits::MAX_SIZE` (30 000;
+/// raster sits below it in the layering and may not depend on it, so the two must stay equal).
+/// A padded side beyond the largest supported comp side has no render use.
+pub const MAX_PADDED_SIDE: u32 = 30_000;
+
 /// Clamp (colour ≤ alpha ≤ 1, NaN → 0) and round half up to `levels` steps (`inv` = 1 / levels):
 /// one pixel of an 8/16 bpc buffer. Values are non-negative after the clamp, so the integer
 /// conversion rounds like `round()` and vectorises.
@@ -161,13 +166,28 @@ impl Image {
         }
         o
     }
-    /// Copy with `pad` transparent pixels on every side.
+    /// The pad [`Image::padded`] applies for a requested `pad`: clamped so neither output side
+    /// exceeds [`MAX_PADDED_SIDE`]. At most `(MAX_PADDED_SIDE - side) / 2`, so
+    /// `side + 2 · pad ≤ MAX_PADDED_SIDE` and overflow is unreachable by construction (a side
+    /// already past the cap gets pad 0). Callers that track where the pixels went (a buffer
+    /// offset) must move by this, not by the requested pad.
+    pub fn effective_pad(&self, pad: u32) -> u32 {
+        pad.min(MAX_PADDED_SIDE.saturating_sub(self.width) / 2).min(MAX_PADDED_SIDE.saturating_sub(self.height) / 2)
+    }
+    /// Copy with [`Image::effective_pad`] transparent pixels on every side.
+    ///
+    /// The clamp keeps the output within the largest image the engine supports (a max-size comp
+    /// frame), so an unbounded pad cannot overflow or size a buffer past that. It is not a memory
+    /// budget: callers that pad by a derived, possibly large amount bound the area themselves
+    /// (`DOF_PAD_BUDGET` in render's `three_d/compose.rs`, `fits()` on the GPU path) or reject an
+    /// oversized pad first (`padded_size`); legitimate bounded pads are byte-identical.
     pub fn padded(&self, pad: u32) -> Image {
-        let mut out = Image::new(self.width + 2 * pad, self.height + 2 * pad);
+        let eff = self.effective_pad(pad);
+        let mut out = Image::new(self.width + 2 * eff, self.height + 2 * eff);
         let ow = out.width as usize;
         for y in 0..self.height as usize {
             let src = &self.data[y * self.width as usize..(y + 1) * self.width as usize];
-            let o = (y + pad as usize) * ow + pad as usize;
+            let o = (y + eff as usize) * ow + eff as usize;
             out.data[o..o + self.width as usize].copy_from_slice(src);
         }
         out
@@ -222,7 +242,7 @@ impl Image {
     }
     /// Straight-alpha 8-bit RGBA (sRGB-encoded values as stored).
     pub fn to_rgba8(&self) -> Vec<u8> {
-        self.map_rgba8(|o, p| {
+        self.map_rgba8(|o, p, _, _| {
             let a = p[3].clamp(0.0, 1.0);
             let inv = if a > 0.0 { 1.0 / p[3] } else { 0.0 };
             for c in 0..3 {
@@ -231,9 +251,20 @@ impl Image {
             o[3] = (a * 255.0 + 0.5) as u8;
         })
     }
+    /// [`Image::to_rgba8`] with the colour dithered ([`dither_u8`]); alpha is rounded.
+    pub fn to_rgba8_dithered(&self) -> Vec<u8> {
+        self.map_rgba8(|o, p, x, y| {
+            let a = p[3].clamp(0.0, 1.0);
+            let inv = if a > 0.0 { 1.0 / p[3] } else { 0.0 };
+            for c in 0..3 {
+                o[c] = dither_u8(p[c] * inv, x, y);
+            }
+            o[3] = (a * 255.0 + 0.5) as u8;
+        })
+    }
     /// Composite over an opaque background colour and return opaque 8-bit RGBA.
     pub fn to_rgba8_over(&self, bg: [f32; 3]) -> Vec<u8> {
-        self.map_rgba8(|o, p| {
+        self.map_rgba8(|o, p, _, _| {
             let k = 1.0 - p[3].clamp(0.0, 1.0);
             for c in 0..3 {
                 o[c] = ((p[c] + bg[c] * k).clamp(0.0, 1.0) * 255.0 + 0.5) as u8;
@@ -241,13 +272,23 @@ impl Image {
             o[3] = 255;
         })
     }
-    /// 8-bit RGBA with each pixel written by `f`, row-parallel.
-    fn map_rgba8(&self, f: impl Fn(&mut [u8; 4], &Px) + Sync) -> Vec<u8> {
+    /// [`Image::to_rgba8_over`] with the colour dithered ([`dither_u8`]).
+    pub fn to_rgba8_over_dithered(&self, bg: [f32; 3]) -> Vec<u8> {
+        self.map_rgba8(|o, p, x, y| {
+            let k = 1.0 - p[3].clamp(0.0, 1.0);
+            for c in 0..3 {
+                o[c] = dither_u8(p[c] + bg[c] * k, x, y);
+            }
+            o[3] = 255;
+        })
+    }
+    /// 8-bit RGBA with each pixel written by `f` (given its x and y), row-parallel.
+    fn map_rgba8(&self, f: impl Fn(&mut [u8; 4], &Px, u32, u32) + Sync) -> Vec<u8> {
         let mut out = vec![0u8; self.data.len() * 4];
         let w = self.width.max(1) as usize;
-        out.par_chunks_mut(w * 4).zip(self.data.par_chunks(w)).for_each(|(o, row)| {
-            for (o, p) in o.as_chunks_mut::<4>().0.iter_mut().zip(row) {
-                f(o, p);
+        out.par_chunks_mut(w * 4).zip(self.data.par_chunks(w)).enumerate().for_each(|(y, (o, row))| {
+            for (x, (o, p)) in o.as_chunks_mut::<4>().0.iter_mut().zip(row).enumerate() {
+                f(o, p, x as u32, y as u32);
             }
         });
         out
@@ -322,6 +363,22 @@ pub fn hash_noise(x: u32, y: u32, seed: u32) -> f32 {
     (h & 0x00ff_ffff) as f32 / 16_777_216.0
 }
 
+/// Seed of the output dither: fixed, so a frame converts to the same bytes every time.
+const DITHER_SEED: u32 = 0x5bd1_e995;
+
+/// A colour value in 0..1 as an 8-bit code, dithered by pixel position (#2022): the value is
+/// scaled to 0..255 and rounded up or down against a per-pixel hash threshold, so the codes of
+/// a smooth gradient average to the gradient instead of stepping in bands. A value already on
+/// an 8-bit code (anything rendered at 8 bpc) comes out unchanged. Deterministic: depends only
+/// on the value and the pixel position, never on a clock or a global generator.
+#[inline]
+pub fn dither_u8(v: f32, x: u32, y: u32) -> u8 {
+    let s = v.clamp(0.0, 1.0) * 255.0;
+    // The threshold stays inside (1e-4, 1 - 1e-4) so float error on an exact code can't flip it.
+    let t = hash_noise(x, y, DITHER_SEED) * (1.0 - 2e-4) + 1e-4;
+    (s + t).floor() as u8
+}
+
 /// A single-channel coverage mask.
 #[derive(Clone, Debug, Default, PartialEq)]
 pub struct Mask {
@@ -346,6 +403,35 @@ impl Mask {
 mod tests {
     use super::*;
 
+    #[test]
+    fn dither_keeps_exact_codes_and_averages_the_rest() {
+        // A value on an 8-bit code is that code at every position.
+        for code in 0..=255u32 {
+            let v = code as f32 / 255.0;
+            for (x, y) in [(0, 0), (1, 0), (17, 3), (1919, 1079), (4095, 4095)] {
+                assert_eq!(dither_u8(v, x, y) as u32, code, "code {code} at ({x}, {y})");
+            }
+        }
+        // Out-of-range and NaN values saturate instead of wrapping.
+        assert_eq!((dither_u8(-3.0, 5, 5), dither_u8(7.0, 5, 5), dither_u8(f32::NAN, 5, 5)), (0, 255, 0));
+        // A value between two codes lands on both, in proportion: the mean over a block is the value.
+        let v = (100.0 + 0.3) / 255.0;
+        let n = 64u32;
+        let sum: u32 = (0..n * n).map(|i| dither_u8(v, i % n, i / n) as u32).sum();
+        let mean = sum as f32 / (n * n) as f32;
+        assert!((mean - 100.3).abs() < 0.03, "{mean}");
+        // Deterministic.
+        assert_eq!(dither_u8(v, 9, 4), dither_u8(v, 9, 4));
+    }
+
+    #[test]
+    fn dithered_conversions_match_the_plain_ones_on_exact_codes() {
+        let src: Vec<u8> = vec![255, 128, 0, 255, 10, 20, 30, 255, 0, 0, 0, 255, 1, 2, 3, 255];
+        let img = Image::from_rgba8(2, 2, &src);
+        assert_eq!(img.to_rgba8_dithered(), img.to_rgba8());
+        assert_eq!(img.to_rgba8_over_dithered([0.0; 3]), img.to_rgba8_over([0.0; 3]));
+    }
+
     #[test]
     fn rgba8_roundtrip() {
         let src: Vec<u8> = vec![255, 128, 0, 255, 10, 20, 30, 128, 0, 0, 0, 0, 1, 2, 3, 4];
@@ -384,4 +470,29 @@ mod tests {
             assert!((0.0..1.0).contains(&n));
         }
     }
+
+    #[test]
+    fn padded_bounds_hostile_pad_at_the_api() {
+        // Fail-before (#2092 class): before the clamp, a caller passing a hostile pad sized an
+        // oversized buffer here — the very OOM this guard exists to stop, now caught in padded().
+        // (Wide-flat source so the clamped-to-cap output stays a test-sized allocation.)
+        let mut img = Image::new(29_990, 2);
+        img.set(29_989, 1, [1.0, 0.0, 0.0, 1.0]);
+        let out = img.padded(u32::MAX);
+        // Width binds first: eff = (MAX_PADDED_SIDE - 29 990) / 2 = 5.
+        assert_eq!((out.width, out.height), (MAX_PADDED_SIDE, 12));
+        // The source lands intact at the clamped offset, not the requested one.
+        assert_eq!(out.get(29_994, 6), [1.0, 0.0, 0.0, 1.0]);
+        assert_eq!(out.get(0, 0), [0.0; 4]); // clamped pad region stays transparent
+    }
+
+    #[test]
+    fn padded_leaves_legit_pads_untouched() {
+        // Anti-over-clamp: an ordinary pad must round exactly, byte for byte.
+        let mut img = Image::new(8, 6);
+        img.set(3, 2, [1.0, 0.0, 0.0, 1.0]);
+        let out = img.padded(4);
+        assert_eq!((out.width, out.height), (16, 14));
+        assert_eq!(out.get(7, 6), [1.0, 0.0, 0.0, 1.0]); // (3+4, 2+4)
+    }
 }

crates/render/src/accel.rs

@@ -184,8 +184,9 @@ impl<'a> Renderer<'a> {
     pub fn layer_aux(&self, ctx: &EvalCtx, layer: &Layer) -> Option<Arc<effectcraft_raster::AuxChannels>> {
         match &layer.source {
             LayerSource::Footage { item } => {
-                let ItemKind::Footage(f) = &self.project.item(*item)?.kind else { return None };
-                let a = self.footage.aux(*item, f, ctx.source_time(layer))?;
+                let item = ctx.media_item(layer, *item);
+                let ItemKind::Footage(f) = &self.project.item(item)?.kind else { return None };
+                let a = self.footage.aux(item, f, ctx.source_time(layer))?;
                 // Aux pixels per layer pixel (the layer is the footage at its nominal size). The
                 // planes are only copied when that changes the scale.
                 let scale = a.width as f64 / f.width as f64;
@@ -332,8 +333,8 @@ impl<'a> Renderer<'a> {
     }
 
     /// Draw a collapsed precomp layer into `canvas` on the CPU.
-    pub fn draw_collapsed_cpu(&self, ctx: &EvalCtx<'a>, layer: &Layer, item: ItemId, canvas: &mut Image) {
-        self.draw_collapsed(ctx, layer, item, canvas, false);
+    pub fn draw_collapsed_cpu(&self, ctx: &EvalCtx<'a>, layer: &'a Layer, collapsed: &crate::Collapsed, canvas: &mut Image) {
+        self.draw_collapsed(ctx, layer, collapsed, canvas, false);
     }
 
     /// The layer's finished buffers (styles included) in the blending space.

crates/render/src/audio.rs

@@ -4,10 +4,13 @@
 //! (Effect > Audio, see [`effectcraft_effects::audio_fx`]) run on each layer's audio before
 //! its levels; Backwards plays the layer's [in, out) span reversed.
 //!
-//! Callers mix in short blocks (one video frame, or an audio device buffer). Effects and levels
-//! are evaluated once per block. To make the result independent of block boundaries, layer
-//! effects are run from a cleared state over a pre-roll of earlier audio and only the block's
-//! tail is kept — so preview playback and export produce identical samples.
+//! Callers mix in short blocks (one video frame, an audio device buffer, or a second of export).
+//! Effect parameters are evaluated once per block. Animated Audio Levels, and animated effects
+//! that work sample by sample (Stereo Mixer), are evaluated on a grid of comp samples every
+//! millisecond instead, so keyframed fades ramp smoothly whatever the block size. To make the
+//! result independent of block boundaries, layer effects are run from a cleared state over a
+//! pre-roll of earlier audio and only the block's tail is kept — so preview playback and export
+//! produce identical samples.
 //!
 //! Time-stretched layers are resampled nearest-sample; reversed (negative stretch) layers are
 //! silent for now.
@@ -85,6 +88,20 @@ fn units_ceil(t: Tick, rate: u32) -> i64 {
     (n.div_euclid(d) + i128::from(n.rem_euclid(d) != 0)) as i64
 }
 
+/// Samples between evaluations of animated levels and per-sample effects: one millisecond, on
+/// a grid of comp sample indices so the result does not depend on where a block starts.
+fn param_step(rate: u32) -> i64 {
+    i64::from(rate / 1000).max(1)
+}
+
+/// Does any property of the group change over time?
+fn animated(g: &effectcraft_project::PropGroup) -> bool {
+    g.children.iter().any(|c| match c {
+        Node::Prop(p) => p.is_animated() || p.has_expression(),
+        Node::Group(sub) => animated(sub),
+    })
+}
+
 fn sample_tick(i: i64, rate: u32) -> Tick {
     // Keep the requested sample when the rate does not divide the tick clock.
     let t = Tick::from_units(i, i64::from(rate));
@@ -189,21 +206,70 @@ impl MixEnv<'_> {
     /// `i0 .. i0 + n`.
     fn layer_audio(&self, l: &Layer, i0: i64, n: usize) -> Vec<f32> {
         let t = sample_tick(i0, self.rate);
-        let fx: Vec<(&str, Params)> = audio_effect_groups(l).map(|(id, g)| (id, self.params(l, g, t))).collect();
+        let fx: Vec<(&str, &effectcraft_project::PropGroup, Params)> = audio_effect_groups(l).map(|(id, g)| (id, g, self.params(l, g, t))).collect();
         if fx.is_empty() {
             return self.layer_raw(l, i0, n, false);
         }
-        let reversed = fx.iter().any(|(id, _)| audio_fx::reverses(id));
-        let pre_s: f64 = fx.iter().map(|(id, p)| audio_fx::preroll(id, p)).sum();
+        let reversed = fx.iter().any(|(id, _, _)| audio_fx::reverses(id));
+        let pre_s: f64 = fx.iter().map(|(id, _, p)| audio_fx::preroll(id, p)).sum();
         let pre = (pre_s * self.rate as f64).ceil() as usize;
-        let mut buf = self.layer_raw(l, i0 - pre as i64, n + pre, reversed);
-        let start = l.layer_time(sample_tick(i0 - pre as i64, self.rate)).seconds();
-        for (id, p) in &fx {
-            audio_fx::process(id, p, &mut buf, self.rate, start);
+        let b0 = i0 - pre as i64;
+        let mut buf = self.layer_raw(l, b0, n + pre, reversed);
+        let start = l.layer_time(sample_tick(b0, self.rate)).seconds();
+        for (id, g, p) in &fx {
+            if audio_fx::per_sample(id) && animated(g) {
+                self.process_stepped(l, id, g, &mut buf, b0);
+            } else {
+                audio_fx::process(id, p, &mut buf, self.rate, start);
+            }
         }
         buf.drain(..pre * 2);
         buf
     }
+
+    /// Run per-sample effect `id` over `buf` (comp samples from `b0`) in pieces of the parameter
+    /// grid, each with the parameters at its first sample.
+    fn process_stepped(&self, l: &Layer, id: &str, g: &effectcraft_project::PropGroup, buf: &mut [f32], b0: i64) {
+        let step = param_step(self.rate);
+        let frames = buf.len() / 2;
+        let mut k = 0usize;
+        while k < frames {
+            let i = b0.saturating_add(k as i64);
+            let next = i.div_euclid(step).saturating_add(1).saturating_mul(step);
+            let end = usize::try_from(next.saturating_sub(b0)).unwrap_or(frames).clamp(k + 1, frames);
+            let t = sample_tick(i, self.rate);
+            if let Some(piece) = buf.get_mut(k * 2..end * 2) {
+                audio_fx::process(id, &self.params(l, g, t), piece, self.rate, l.layer_time(t).seconds());
+            }
+            k = end;
+        }
+    }
+
+    /// Linear gains (left, right) of the layer's Audio Levels for comp samples `i0 .. i0 + n`.
+    /// Animated levels are evaluated on the parameter grid and interpolated in dB in between.
+    fn level_gains(&self, l: &Layer, i0: i64, n: usize) -> Vec<[f32; 2]> {
+        let Some(pr) = l.props.sub("audio").and_then(|g| g.get("levels")) else { return vec![[1.0, 1.0]; n] };
+        let db = |i: i64| self.ctx(sample_tick(i, self.rate)).value(l, pr).as_vec2();
+        let gain = |[a, b]: [f64; 2]| [db_to_gain(a), db_to_gain(b)];
+        if !pr.is_animated() && !pr.has_expression() {
+            return vec![gain(db(i0)); n];
+        }
+        let step = param_step(self.rate);
+        let end = i0.saturating_add(n as i64);
+        let mut out = Vec::with_capacity(n);
+        let mut k = i0.div_euclid(step).saturating_mul(step);
+        let mut lo = db(k);
+        while k < end {
+            let hi = db(k.saturating_add(step));
+            for i in k.max(i0)..k.saturating_add(step).min(end) {
+                let f = (i - k) as f64 / step as f64;
+                out.push(gain([lo[0] + (hi[0] - lo[0]) * f, lo[1] + (hi[1] - lo[1]) * f]));
+            }
+            k = k.saturating_add(step);
+            lo = hi;
+        }
+        out
+    }
 }
 
 /// Shared inputs for composition audio mixing, including nested compositions.
@@ -234,25 +300,18 @@ fn mix_into(sources: &AudioSources<'_>, comp_id: ItemId, start: Tick, out: &mut
         if a >= b {
             continue;
         }
-        let t_a = sample_tick(s0 + a as i64, rate);
-        let (ll, lr) = levels(&env, l, t_a);
-        if ll == 0.0 && lr == 0.0 {
+        let gains = env.level_gains(l, s0 + a as i64, b - a);
+        if gains.iter().all(|g| *g == [0.0, 0.0]) {
             continue;
         }
         let buf = env.layer_audio(l, s0 + a as i64, b - a);
-        for (i, f) in buf.as_chunks::<2>().0.iter().enumerate() {
-            out[(a + i) * 2] += f[0] * ll;
-            out[(a + i) * 2 + 1] += f[1] * lr;
+        for (i, (f, g)) in buf.as_chunks::<2>().0.iter().zip(&gains).enumerate() {
+            out[(a + i) * 2] += f[0] * g[0];
+            out[(a + i) * 2 + 1] += f[1] * g[1];
         }
     }
 }
 
-fn levels(env: &MixEnv, l: &Layer, t: Tick) -> (f32, f32) {
-    let Some(g) = l.props.sub("audio") else { return (1.0, 1.0) };
-    let [a, b] = env.ctx(t).v2(l, g, "levels", [0.0, 0.0]);
-    (db_to_gain(a), db_to_gain(b))
-}
-
 /// A min/max peak summary of interleaved stereo audio for waveform drawing: one entry per
 /// `bin` sample frames, `[min L, max L, min R, max R]`.
 pub fn peak_summary(samples: &[f32], bin: usize) -> Vec<[f32; 4]> {

crates/render/src/cache.rs

@@ -479,6 +479,19 @@ fn group_has(g: &PropGroup, match_id: &str) -> bool {
 
 /// Feed every property of `g` that can change over time (keyframes or expression) as its value
 /// at the context time. The static structure is hashed separately.
+/// Mix the collapsed-instance overrides that target `id` into a cache key. They replace values
+/// without editing the layer, so a key without them would reuse another instance's buffer.
+fn hash_overrides(h: &mut KeyHasher, ctx: &EvalCtx, id: effectcraft_project::LayerId) {
+    for o in ctx.property_overrides.iter().filter(|o| o.layer == id) {
+        o.prop.hash(h);
+        o.font.hash(h);
+        hash_debug(h, &o.value);
+    }
+    for m in ctx.media_overrides.iter().filter(|m| m.layer == id) {
+        m.item.hash(h);
+    }
+}
+
 fn hash_values(h: &mut KeyHasher, ctx: &EvalCtx, layer: &Layer, g: &PropGroup) {
     for c in &g.children {
         match c {
@@ -605,8 +618,9 @@ fn key_any(ctx: &EvalCtx, layer: &Layer, scale: f64, draft: bool, blur: bool, fo
             hash_debug(&mut h, s);
         }
         LayerSource::Text | LayerSource::Shape => {}
-        LayerSource::Footage { item } if footage || still_footage(ctx, *item) => {
-            let it = ctx.project.item(*item)?;
+        LayerSource::Footage { item } if footage || still_footage(ctx, ctx.media_item(layer, *item)) => {
+            let item = ctx.media_item(layer, *item);
+            let it = ctx.project.item(item)?;
             let ItemKind::Footage(f) = &it.kind else { return None };
             hash_debug(&mut h, f);
             // A proxy (and its Use Proxy switch) changes the pixels.
@@ -629,6 +643,10 @@ fn key_any(ctx: &EvalCtx, layer: &Layer, scale: f64, draft: bool, blur: bool, fo
     scale.to_bits().hash(&mut h);
     draft.hash(&mut h);
     layer.id.hash(&mut h);
+    // Collapsed-instance overrides replace values without editing the nested layer, so mix them
+    // into the key: a Font override, effect parameter or any other source-affecting override
+    // must not reuse another instance's processed buffer.
+    hash_overrides(&mut h, ctx, layer.id);
     hash_debug(&mut h, &layer.source);
     // (Audio, Lock and Shy don't change pixels.)
     hash_debug(&mut h, &layer.switches.pixels());

crates/render/src/cache/dependencies.rs

@@ -3,7 +3,7 @@
 //! cyclic/over-budget graphs or expressions sampled at unknown times.
 use super::{KeyHasher, hash_debug, hash_values};
 use crate::EvalCtx;
-use effectcraft_project::{ItemId, ItemKind, Layer, LayerId, LayerSource, Node, PropGroup};
+use effectcraft_project::{ItemId, ItemKind, Layer, LayerId, LayerSource, LightKind, Node, PropGroup};
 use std::hash::Hash;
 
 pub(super) fn hash(h: &mut KeyHasher, ctx: &EvalCtx, layer: &Layer, effects: Option<usize>) -> Option<()> {
@@ -63,11 +63,68 @@ impl Dependencies<'_> {
         Some(())
     }
 
+    /// What a referenced 3D model or primitive layer's solo render depends on: the layer itself
+    /// (geometry, materials, switches, in/out), its animated values and transform at the time,
+    /// the mesh item, the comp's camera (with its depth of field) and its lights at the time
+    /// (the lights are off in draft 3D, and the renderer setting changes the pixels), the model's
+    /// layer time while it plays an animation clip, and the in/out gate (outside the range the
+    /// read is transparent). An Environment light's image can be any layer's render: with one on
+    /// the read is not cached. Comp size and render scale are in the owner's key already.
+    fn soloed_model(&mut self, ctx: &EvalCtx, layer: &Layer) -> Option<()> {
+        self.remaining = self.remaining.checked_sub(1)?;
+        // Expressions sampled at other times: not cacheable, as in the ordinary path.
+        if (self.other_times || super::reads_other_times(layer, None)) && super::has_expression(&layer.props) {
+            return None;
+        }
+        hash_debug(self.h, layer);
+        hash_values(self.h, ctx, layer, &layer.props);
+        hash_debug(self.h, &ctx.world_matrix(layer));
+        if let Some(item) = layer.source.item() {
+            hash_debug(self.h, &ctx.project.item(item));
+        }
+        // The solo render goes through the comp's camera and lights. The camera's depth of
+        // field blurs it (focus, aperture, iris, highlights) — none of that is in the
+        // projection hashed above.
+        hash_debug(self.h, &ctx.camera());
+        hash_debug(self.h, &crate::three_d::active_camera(ctx).dof);
+        hash_debug(self.h, &crate::three_d::light::lights_at(ctx));
+        hash_debug(self.h, &ctx.comp.draft_3d);
+        hash_debug(self.h, &ctx.comp.renderer);
+        // An Environment light's image lights Advanced 3D models (its source can be any
+        // layer's render, or any environment layer) — too open-ended to hash: while one is
+        // on (and lighting: Draft 3D lights nothing), don't cache the read.
+        if ctx.comp.renderer == effectcraft_project::Renderer::Advanced3D
+            && !ctx.comp.draft_3d
+            && ctx.comp.layers.iter().any(|l| {
+                l.is_light() && l.switches.video && l.is_active_at(ctx.time) && matches!(l.source, LayerSource::Light { kind: LightKind::Environment })
+            })
+        {
+            return None;
+        }
+        // A model with an animation clip selected is posed at its layer time (Animation Speed
+        // and Looping are static, hashed above): every time is its own entry. Without one the
+        // pose is the same at every time: keep the static key.
+        if layer.props.sub("geometryOptions").map_or(0, |g| ctx.e(layer, g, "animation")) != 0 {
+            layer.layer_time(ctx.time).0.hash(self.h);
+        }
+        // Outside the layer's in/out range the read is transparent: fold the gate in, so a
+        // static model renders once inside it and again when it leaves.
+        layer.is_active_at(ctx.time).hash(self.h);
+        Some(())
+    }
+
     fn layer(&mut self, ctx: &EvalCtx, layer: &Layer) -> Option<()> {
         let id = (ctx.comp_id, layer.id);
         if self.path.len() > crate::MAX_FX_DEPTH || self.path.contains(&id) {
             return None;
         }
+        // A referenced 3D model or primitive layer renders through the comp's camera and lights
+        // (an effect layer parameter reads it that way — Create 3D Layer Instance): hash what
+        // moves its pixels, so the owner keeps a cache entry that changes when any of it does.
+        if layer.source.is_model() {
+            self.soloed_model(ctx, layer)?;
+            return Some(());
+        }
         self.remaining = self.remaining.checked_sub(1)?;
         if (self.other_times || super::reads_other_times(layer, None)) && super::has_expression(&layer.props) {
             return None;
@@ -76,6 +133,9 @@ impl Dependencies<'_> {
         // Include transforms/parents as well as pixels: selected-layer anchors and
         // continuously rasterized sources can depend on them.
         hash_debug(self.h, layer);
+        // A referenced layer's static values can be overridden by the collapsed instance without
+        // editing it (`hash_values` only sees animated ones), so the owner's key needs them too.
+        super::hash_overrides(self.h, ctx, layer.id);
         hash_values(self.h, ctx, layer, &layer.props);
         hash_debug(self.h, &ctx.world_matrix(layer));
         // A cached owner never runs this layer's effects, so the comp camera and lights its
@@ -88,6 +148,10 @@ impl Dependencies<'_> {
         }
         match layer.source {
             LayerSource::Solid { item } | LayerSource::Footage { item } | LayerSource::Comp { item } => {
+                let item = match layer.source {
+                    LayerSource::Footage { .. } => ctx.media_item(layer, item),
+                    _ => item,
+                };
                 let source = ctx.project.item(item);
                 hash_debug(self.h, &source);
                 if let Some(source) = source {

crates/render/src/eval.rs

@@ -39,17 +39,33 @@ pub struct EvalCtx<'a> {
     /// Footage frames for expressions that read rendered pixels (`sampleImage`): the renderer's
     /// own source while rendering; `None` renders footage as transparent.
     pub footage: Option<&'a dyn crate::FootageSource>,
+    /// Property values overridden by the Essential Properties of a collapsed precomp instance.
+    pub property_overrides: &'a [crate::PropertyOverride],
+    /// Media Replacement values overridden by the Essential Properties of a collapsed precomp
+    /// instance.
+    pub media_overrides: &'a [crate::MediaOverride],
 }
 
 impl<'a> EvalCtx<'a> {
     pub fn new(project: &'a Project, comp_id: ItemId, comp: &'a Comp, time: Tick) -> EvalCtx<'a> {
-        EvalCtx { project, comp_id, comp, time, expr: None, footage: None }
+        EvalCtx { project, comp_id, comp, time, expr: None, footage: None, property_overrides: &[], media_overrides: &[] }
     }
     pub fn at(&self, time: Tick) -> EvalCtx<'a> {
         EvalCtx { time, ..*self }
     }
     /// Value of a property at the context time (keyframes, then expression).
     pub fn value(&self, layer: &Layer, prop: &Property) -> Value {
+        // A collapsed precomp instance's Essential Property override replaces the base value;
+        // its expression (if any) still runs, and sees the overrides of this context.
+        if let Some(o) = self.property_overrides.iter().rev().find(|o| o.layer == layer.id && o.prop == prop.uid) {
+            let v = o.value(layer, prop, self.time);
+            if prop.has_expression()
+                && let Some(h) = self.expr
+            {
+                return h.eval(self, layer, prop, &v).unwrap_or(v);
+            }
+            return v;
+        }
         // Separated Position reads as the combination of X/Y/Z Position.
         if prop.match_id == "position"
             && let Some(tr) = layer.transform()
@@ -145,13 +161,15 @@ impl<'a> EvalCtx<'a> {
     /// Source pixel aspect relative to the comp's: non-square footage (or solids, or precomps
     /// with another pixel aspect) is stretched horizontally by this factor in the comp.
     pub fn par_ratio(&self, layer: &Layer) -> f64 {
-        let par = match &layer.source {
-            LayerSource::Footage { item } | LayerSource::Solid { item } | LayerSource::Comp { item } => match self.project.item(*item).map(|i| &i.kind) {
-                Some(effectcraft_project::ItemKind::Footage(f)) => f.pixel_aspect,
-                Some(effectcraft_project::ItemKind::Solid(s)) => s.pixel_aspect,
-                Some(effectcraft_project::ItemKind::Comp(c)) => c.pixel_aspect,
-                _ => 1.0,
-            },
+        let item = match &layer.source {
+            LayerSource::Footage { item } => Some(self.media_item(layer, *item)),
+            LayerSource::Solid { item } | LayerSource::Comp { item } => Some(*item),
+            _ => None,
+        };
+        let par = match item.and_then(|item| self.project.item(item)).map(|i| &i.kind) {
+            Some(effectcraft_project::ItemKind::Footage(f)) => f.pixel_aspect,
+            Some(effectcraft_project::ItemKind::Solid(s)) => s.pixel_aspect,
+            Some(effectcraft_project::ItemKind::Comp(c)) => c.pixel_aspect,
             _ => 1.0,
         };
         let r = par / if self.comp.pixel_aspect > 0.0 { self.comp.pixel_aspect } else { 1.0 };
@@ -237,9 +255,27 @@ impl<'a> EvalCtx<'a> {
             (Mat3([[m[0][0], m[0][1], m[0][3]], [m[1][0], m[1][1], m[1][3]], [0.0, 0.0, 1.0]]), 0.0)
         }
     }
+    /// The footage item a layer uses, honouring this instance's Media Replacement override.
+    pub fn media_item(&self, layer: &Layer, item: ItemId) -> ItemId {
+        self.media_overrides.iter().rev().find(|m| m.layer == layer.id).map_or(item, |m| m.item)
+    }
+
+    /// Size of a layer's source in layer pixels, honouring Media Replacement.
+    pub fn source_size(&self, layer: &Layer) -> (u32, u32) {
+        let item = match &layer.source {
+            LayerSource::Footage { item } => Some(self.media_item(layer, *item)),
+            LayerSource::Comp { item } | LayerSource::Solid { item } => Some(*item),
+            _ => None,
+        };
+        match layer.source {
+            LayerSource::Null => (100, 100),
+            _ => item.and_then(|item| self.project.item(item)).and_then(|i| i.dimensions()).unwrap_or((0, 0)),
+        }
+    }
+
     /// [`effect_bounds`] of a layer of this comp.
     pub fn effect_bounds(&self, layer: &Layer) -> ([f64; 2], [f64; 2]) {
-        effect_bounds(self.project, self.comp, layer)
+        effect_bounds_of(self.comp, self.source_size(layer))
     }
     /// Effect space (see [`effect_bounds`]) → comp matrix.
     pub fn effect_to_comp(&self, layer: &Layer) -> Mat3 {
@@ -248,6 +284,20 @@ impl<'a> EvalCtx<'a> {
     }
 }
 
+impl crate::PropertyOverride {
+    fn value(&self, layer: &Layer, prop: &Property, time: Tick) -> Value {
+        if self.font {
+            // A Font control merges only the font into the target text, as
+            // `essential::with_overrides` does.
+            let mut value = prop.value_at(layer.layer_time(time));
+            effectcraft_project::essential::merge_font(&mut value, &self.value);
+            value
+        } else {
+            self.value.clone()
+        }
+    }
+}
+
 /// The protected regions of a comp (Responsive Design — Time markers), merged, sorted and
 /// clamped to the comp, in seconds.
 pub fn protected_regions(comp: &Comp) -> Vec<(f64, f64)> {
@@ -321,7 +371,11 @@ pub fn responsive_source_time(comp: &Comp, stretch: f64, elapsed: f64) -> Option
 /// surrounds. Effects work in **effect space**, measured from that corner (After Effects' layer
 /// space for effect points: a shape layer's default effect point is its bounds' centre).
 pub fn effect_bounds(project: &Project, comp: &Comp, layer: &Layer) -> ([f64; 2], [f64; 2]) {
-    match source_size(project, layer) {
+    effect_bounds_of(comp, source_size(project, layer))
+}
+
+fn effect_bounds_of(comp: &Comp, size: (u32, u32)) -> ([f64; 2], [f64; 2]) {
+    match size {
         (0, _) => {
             let (w, h) = (comp.width as f64, comp.height as f64);
             ([w, h], [-w / 2.0, -h / 2.0])

crates/render/src/frames.rs

@@ -1,6 +1,6 @@
 use super::footage::NoFootage;
 use super::opts::RenderOpts;
-use super::{EvalCtx, Footage, FrameBlend, FrameRate, Image, ItemId, Layer, LayerSource, Project, Renderer, TICKS_PER_SECOND, Tick, shapes, source_size, text};
+use super::{EvalCtx, Footage, FrameBlend, FrameRate, Image, ItemId, Layer, LayerSource, Project, Renderer, TICKS_PER_SECOND, Tick, shapes, text};
 
 /// The layer's frame blending mode, if the comp's Enable Frame Blending switch is on.
 /// One field of an interlaced frame as a full frame: the field's lines (`parity` 0 = even /
@@ -132,7 +132,7 @@ pub fn content_bounds(ctx: &EvalCtx, layer: &effectcraft_project::Layer) -> Opti
         LayerSource::Shape => layer.props.sub("contents").and_then(|c| shapes::content_bounds(ctx, layer, c)).map(|r| [r.x0, r.y0, r.x1, r.y1]),
         LayerSource::Camera | LayerSource::Light { .. } => None,
         _ => {
-            let (w, h) = source_size(ctx.project, layer);
+            let (w, h) = ctx.source_size(layer);
             (w > 0 && h > 0).then_some([0.0, 0.0, w as f64, h as f64])
         }
     }

crates/render/src/fx_host.rs

@@ -72,6 +72,14 @@ impl EffectHost for FxHost<'_, '_, '_> {
             return None;
         }
         let sub = self.r.nested();
+        // A 3D model or primitive layer has no 2D source of its own: an effect referencing one
+        // reads it as After Effects does — the layer rendered on its own through the comp's
+        // camera (Create 3D Layer Instance's effect), in the layer's effect space (the
+        // comp, centred on the layer's anchor).
+        if other.source.is_model() {
+            let buf = sub.solo_3d(self.ctx, other);
+            return Some(self.pixels(other, buf, false));
+        }
         // The cached layer buffer is shared; effects get their own copy.
         let buf = if masks_and_effects { (*sub.content_buf(self.ctx, other)?).clone() } else { sub.source(self.ctx, other)? };
         Some(self.pixels(other, buf, true))
@@ -90,12 +98,13 @@ impl EffectHost for FxHost<'_, '_, '_> {
     fn audio(&self, id: u64, start: f64, frames: usize, rate: u32) -> Option<Vec<f32>> {
         let other = self.ctx.layer(effectcraft_project::LayerId(id))?;
         let LayerSource::Footage { item } = &other.source else { return None };
-        let ItemKind::Footage(f) = &self.r.project.item(*item)?.kind else { return None };
+        let item = self.ctx.media_item(other, *item);
+        let ItemKind::Footage(f) = &self.r.project.item(item)?.kind else { return None };
         if !f.has_audio {
             return None;
         }
         let st = other.layer_time(Tick::from_seconds_f64(start));
-        self.r.footage.audio(*item, f, st, frames, rate)
+        self.r.footage.audio(item, f, st, frames, rate)
     }
 
     fn self_at(&self, layer_time: f64, effects: usize) -> Option<Buf> {

crates/render/src/layers.rs

@@ -2,7 +2,7 @@ use super::frames::adaptive_samples;
 use super::opts::{LayerTiming, Through};
 use super::{
     Arc, BlendMode, Buf, Comp, EvalCtx, Image, IndexedParallelIterator, IntoParallelRefIterator, IntoParallelRefMutIterator, Layer, LayerSource, Mat3,
-    MatteKind, ParallelIterator, Quality, Region, Renderer, Sampling, Tick, WarpOpts, cache, color, composite_warp_changed, masks, source_size, styles, vec2,
+    MatteKind, ParallelIterator, Quality, Region, Renderer, Sampling, Tick, WarpOpts, cache, color, composite_warp_changed, masks, styles, vec2,
 };
 
 /// Blend policy for placing a layer, including optional output-depth quantization.
@@ -52,7 +52,7 @@ impl<'a> Renderer<'a> {
             }
         }
         let t0 = web_time::Instant::now();
-        let size = source_size(self.project, layer);
+        let size = ctx.source_size(layer);
         let layer_size = if size.0 == 0 { [ctx.comp.width as f64, ctx.comp.height as f64] } else { [size.0 as f64, size.1 as f64] };
         let st = styles::render(ctx, layer, &content, layer_size);
         if let Some(t) = timing {

crates/render/src/lib.rs

@@ -60,6 +60,7 @@ pub use layers::{Placement, StyledLayer};
 pub(crate) use opts::Collapse3d;
 pub use opts::{LayerTiming, RenderOpts};
 use opts::{MAX_THROUGH, Through};
+pub use pipeline::{Collapsed, MediaOverride, PropertyOverride};
 
 pub struct Renderer<'a> {
     pub project: &'a Project,

crates/render/src/pipeline.rs

@@ -7,6 +7,8 @@ use super::{
     Arc, AutoKey, AutoPick, BlendMode, Buf, Comp, EffectCtx, EffectEnv, EvalCtx, Footage, FootageKind, FrameBlend, FrameRate, GroupKind, Image, ItemId,
     ItemKind, Layer, LayerCache, LayerSource, Params, Project, Quality, Region, Renderer, Tick, cache, color, masks, shapes, styles, text, three_d, vec2,
 };
+use effectcraft_keyframe::Value;
+use effectcraft_project::LayerId;
 
 /// Coordinate space and stack range shared by CPU and accelerated effect evaluation.
 #[derive(Clone, Copy)]
@@ -16,6 +18,88 @@ pub(crate) struct EffectStack {
     pub origin: [f64; 2],
 }
 
+/// A property value an Essential Properties override gives a layer of a collapsed precomp.
+#[derive(Clone, Debug)]
+pub struct PropertyOverride {
+    pub(crate) layer: LayerId,
+    pub(crate) prop: u64,
+    pub(crate) value: Value,
+    /// A Font control changes only the font of the target text, not its text.
+    pub(crate) font: bool,
+}
+
+/// A Media Replacement an Essential Properties override gives a footage layer of a collapsed
+/// precomp.
+#[derive(Clone, Copy, Debug)]
+pub struct MediaOverride {
+    pub(crate) layer: LayerId,
+    pub(crate) item: ItemId,
+}
+
+impl MediaOverride {
+    /// A Media Replacement of `layer`'s footage by `item`.
+    pub fn new(layer: LayerId, item: ItemId) -> Self {
+        MediaOverride { layer, item }
+    }
+}
+
+/// A collapsed precomp layer: the nested comp and the instance overrides that apply to it.
+pub struct Collapsed {
+    pub item: ItemId,
+    pub(crate) property_overrides: Vec<PropertyOverride>,
+    pub(crate) media_overrides: Vec<MediaOverride>,
+}
+
+/// The property and media overrides of a collapsed precomp layer. `None` when its Essential
+/// Properties group or the source comp's definitions are missing (the flattened path then
+/// preserves the old behaviour).
+fn collapsed_instance(ctx: &EvalCtx, layer: &Layer, item: ItemId) -> Option<(Vec<PropertyOverride>, Vec<MediaOverride>)> {
+    use effectcraft_project::essential::{self, ControlType, EgKind};
+    let over = essential::overridden(layer);
+    if over.is_empty() {
+        return Some((vec![], vec![]));
+    }
+    let g = essential::group(layer)?;
+    let eg = ctx.project.comp(item)?.essential.as_ref()?;
+    let mut property = vec![];
+    let mut fonts: Vec<PropertyOverride> = vec![];
+    let mut media = vec![];
+    g.walk("", &mut |_, p| {
+        if !over.contains(&p.uid) {
+            return;
+        }
+        let Some(control) = essential::control_of(&p.match_id) else { return };
+        let Some(ctl) = eg.resolve(control) else { return };
+        let value = ctx.value(layer, p);
+        match &ctl.kind {
+            EgKind::Property { .. } => {
+                let font = ctl.as_type == Some(ControlType::Font);
+                for (layer, prop) in ctl.kind.targets() {
+                    let o = PropertyOverride { layer, prop, value: value.clone(), font };
+                    if font { fonts.push(o) } else { property.push(o) }
+                }
+            }
+            EgKind::Media { layer: target } => {
+                let Value::Scalar(id) = value else { return };
+                let item = ItemId(id.max(0.0) as u64);
+                if matches!(ctx.project.item(item).map(|i| &i.kind), Some(ItemKind::Footage(_))) {
+                    media.push(MediaOverride { layer: *target, item });
+                }
+            }
+            _ => {}
+        }
+    });
+    // A Font control merges into the text its instance shows, after a whole-value (Text) override
+    // of the same property, as `essential::with_overrides` does: keep one entry per property.
+    for f in fonts {
+        match property.iter_mut().rev().find(|o| o.layer == f.layer && o.prop == f.prop) {
+            Some(o) => effectcraft_project::essential::merge_font(&mut o.value, &f.value),
+            None => property.push(f),
+        }
+    }
+    Some((property, media))
+}
+
 impl<'a> Renderer<'a> {
     pub fn new(project: &'a Project, footage: &'a dyn FootageSource, opts: RenderOpts) -> Renderer<'a> {
         Renderer {
@@ -122,8 +206,10 @@ impl<'a> Renderer<'a> {
 
     /// The nested comp of a precomp layer whose transformations collapse into this comp: the
     /// Collapse Transformations switch is on and the layer has no masks, effects or layer
-    /// styles (those force a flattened render of the precomp, as in After Effects).
-    pub fn collapsed(&self, ctx: &EvalCtx, layer: &Layer) -> Option<ItemId> {
+    /// styles (those force a flattened render of the precomp, as in After Effects). Essential
+    /// Properties overrides travel with it and are applied as the nested layers are evaluated,
+    /// so the nested comp is not rasterised at its frame.
+    pub fn collapsed(&self, ctx: &EvalCtx, layer: &Layer) -> Option<Collapsed> {
         if !layer.switches.collapse || layer.switches.adjustment || self.depth > 12 {
             return None;
         }
@@ -140,24 +226,37 @@ impl<'a> Renderer<'a> {
         if styles::active(ctx, layer) {
             return None;
         }
-        // Instance overrides (Essential Properties) need the nested comp rendered on its own.
-        if !effectcraft_project::essential::overridden(layer).is_empty() {
+        // A composition proxy or frame blending is drawn by the flattened path (`precomp_source`);
+        // collapsing renders the nested comp directly and would ignore both.
+        if self.proxy_for(*item).is_some() || frame_blend_mode(ctx, layer) != FrameBlend::Off {
             return None;
         }
-        Some(*item)
+        let (property_overrides, media_overrides) = collapsed_instance(ctx, layer, *item)?;
+        Some(Collapsed { item: *item, property_overrides, media_overrides })
     }
 
     /// A renderer and context that draw a collapsed precomp's layers straight into this comp:
     /// their transforms are concatenated with the precomp layer's (one resample, no
     /// rasterisation at the precomp's bounds), their opacity multiplied by `opacity`, and their
     /// 3D layers use this comp's camera and lights.
-    pub fn collapse_into(&self, ctx: &EvalCtx<'a>, layer: &'a Layer, item: ItemId, opacity: f32) -> Option<(Renderer<'a>, EvalCtx<'a>)> {
+    pub fn collapse_into<'p>(&self, ctx: &EvalCtx<'a>, layer: &'a Layer, collapsed: &'p Collapsed, opacity: f32) -> Option<(Renderer<'p>, EvalCtx<'p>)>
+    where
+        'a: 'p,
+    {
+        let item = collapsed.item;
         let nc = self.project.comp(item)?;
         let t = ctx.nested_time(layer);
         if !nc.covers(t) {
             return None;
         }
-        let nctx = EvalCtx { comp_id: item, comp: nc, time: t, ..*ctx };
+        let nctx = EvalCtx {
+            comp_id: item,
+            comp: nc,
+            time: t,
+            property_overrides: &collapsed.property_overrides,
+            media_overrides: &collapsed.media_overrides,
+            ..*ctx
+        };
         let (l2c, _) = ctx.layer_to_comp(layer);
         let outer = Some(self.outer.map_or(l2c, |o| o * l2c));
         let world = ctx.world_matrix(layer);
@@ -189,19 +288,19 @@ impl<'a> Renderer<'a> {
     /// that then takes the precomp layer's track matte, Preserve Transparency and blend mode.
     /// Returns the region left to re-quantise (nested layers drawn straight into `canvas`
     /// quantise their own footprints).
-    pub(crate) fn draw_collapsed(&self, ctx: &EvalCtx<'a>, layer: &Layer, item: ItemId, canvas: &mut Image, blank: bool) -> Region {
+    pub(crate) fn draw_collapsed(&self, ctx: &EvalCtx<'a>, layer: &'a Layer, collapsed: &Collapsed, canvas: &mut Image, blank: bool) -> Region {
         let opacity = ctx.opacity(layer) as f32 * self.opacity_mul;
         if opacity <= 0.0 {
             return Region::Empty;
         }
         let matte = layer.track_matte.is_some_and(|tm| tm.layer != layer.id && ctx.comp.layer(tm.layer).is_some());
         if layer.blend_mode == BlendMode::Normal && !matte && !layer.preserve_transparency {
-            if let Some((sub, nctx)) = self.collapse_into(ctx, layer, item, opacity) {
+            if let Some((sub, nctx)) = self.collapse_into(ctx, layer, collapsed, opacity) {
                 sub.draw_comp(&nctx, canvas, blank);
             }
             return Region::Empty;
         }
-        let Some((sub, nctx)) = self.collapse_into(ctx, layer, item, 1.0) else { return Region::Empty };
+        let Some((sub, nctx)) = self.collapse_into(ctx, layer, collapsed, 1.0) else { return Region::Empty };
         let mut iso = Image::new(canvas.width, canvas.height);
         sub.draw_comp(&nctx, &mut iso, true);
         self.composite_iso(ctx, layer, iso, canvas, opacity);
@@ -230,6 +329,7 @@ impl<'a> Renderer<'a> {
         let continuous = match layer.source {
             LayerSource::Text | LayerSource::Shape => true,
             LayerSource::Footage { item } => {
+                let item = ctx.media_item(layer, item);
                 layer.switches.collapse && matches!(self.project.item(item).map(|i| &i.kind), Some(ItemKind::Footage(f)) if is_vector_footage(f))
             }
             _ => false,
@@ -267,7 +367,7 @@ impl<'a> Renderer<'a> {
     }
 
     pub(crate) fn ctx(&self, comp_id: ItemId, comp: &'a Comp, t: Tick) -> EvalCtx<'a> {
-        EvalCtx { project: self.project, comp_id, comp, time: t, expr: self.expr, footage: Some(self.footage) }
+        EvalCtx { project: self.project, comp_id, comp, time: t, expr: self.expr, footage: Some(self.footage), property_overrides: &[], media_overrides: &[] }
     }
 
     /// This renderer with another accelerator (or none): the passes of
@@ -406,7 +506,7 @@ impl<'a> Renderer<'a> {
                 blank = false;
             } else {
                 let changed = match self.collapsed(ctx, visible[i]) {
-                    Some(item) => self.draw_collapsed(ctx, visible[i], item, canvas, blank),
+                    Some(collapsed) => self.draw_collapsed(ctx, visible[i], &collapsed, canvas, blank),
                     None => self.draw_layer(ctx, visible[i], canvas, blank),
                 };
                 i += 1;
@@ -637,7 +737,8 @@ impl<'a> Renderer<'a> {
                 Some(Buf { img: sub.comp_frame(*item, lt), offset: [0.0; 2], scale: bs })
             }
             LayerSource::Footage { item } => {
-                let it = self.project.item(*item)?;
+                let item = ctx.media_item(layer, *item);
+                let it = self.project.item(item)?;
                 let ItemKind::Footage(f) = &it.kind else { return None };
                 if !f.has_video {
                     return None;
@@ -645,7 +746,7 @@ impl<'a> Renderer<'a> {
                 // Continuously rasterised vector footage: drawn at the on-screen scale.
                 if layer.switches.collapse && is_vector_footage(f) {
                     let k = self.raster_scale(ctx, layer);
-                    if let Some(img) = self.footage.vector_frame(*item, f, k) {
+                    if let Some(img) = self.footage.vector_frame(item, f, k) {
                         let mut buf = Buf { img: (*img).clone(), offset: [0.0; 2], scale: k };
                         if let Some(c) = self.pipe.media_in(f) {
                             color::convert(&mut buf.img, &c);
@@ -655,10 +756,10 @@ impl<'a> Renderer<'a> {
                 }
                 let lt = ctx.source_time(layer);
                 // The proxy is decoded instead, at its own size, and fills the footage's frame.
-                let proxy = self.proxy_for(*item);
+                let proxy = self.proxy_for(item);
                 let pf = proxy.unwrap_or(f);
                 let size = self.reduced_size(f.width, f.height).filter(|_| proxy.is_none());
-                let img = self.footage_frame(ctx, layer, *item, pf, lt, size)?;
+                let img = self.footage_frame(ctx, layer, item, pf, lt, size)?;
                 Some(self.footage_buf(&img, pf, f.width, f.height))
             }
             LayerSource::Text => Some(self.authored(text::render(ctx, layer, self.raster_scale(ctx, layer)))),
@@ -836,6 +937,30 @@ impl<'a> Renderer<'a> {
         self.source(ctx, layer)
     }
 
+    /// A 3D model or primitive layer rendered on its own, through the comp's camera: what an
+    /// effect layer parameter reads when it references one, as After Effects, which renders 3D
+    /// layers through the active camera. The comp's pixels at this render's scale; the layer's
+    /// blend mode, track matte and video switch don't apply (a source read, not a composite —
+    /// the solo clone of a 3D track matte, see `three_d::adv`).
+    pub(crate) fn solo_3d(&self, ctx: &EvalCtx, layer: &Layer) -> Buf {
+        let s = self.opts.scale;
+        let w = ((ctx.comp.width as f64 * s).ceil() as u32).max(1);
+        let h = ((ctx.comp.height as f64 * s).ceil() as u32).max(1);
+        let mut canvas = Image::new(w, h);
+        // Outside the layer's in/out points there is nothing to read: the copy is transparent
+        // there, like any other layer reference (the 3D pipelines don't gate on the range).
+        if !layer.is_active_at(ctx.time) {
+            return Buf { img: canvas, offset: [0.0; 2], scale: s };
+        }
+        let mut solo = layer.clone();
+        solo.track_matte = None;
+        solo.blend_mode = effectcraft_color::BlendMode::Normal;
+        solo.preserve_transparency = false;
+        solo.switches.video = true;
+        three_d::compose::draw_run(self, ctx, &[&solo], &mut canvas);
+        Buf { img: canvas, offset: [0.0; 2], scale: s }
+    }
+
     /// Layer pixels after source → masks → effects (no layer styles).
     pub fn content_buf(&self, ctx: &EvalCtx, layer: &Layer) -> Option<Arc<Buf>> {
         self.content_buf_timed(ctx, layer, None).map(|(b, _)| b)

crates/render/src/tests.rs

@@ -1276,3 +1276,194 @@ fn workers_rendering_a_layer_at_once_share_one_buffer() {
     assert!(bufs.iter().all(|b| std::sync::Arc::ptr_eq(b, &bufs[0])), "one shared buffer");
     assert_eq!(cache.stats().entries, 1);
 }
+
+// ------------------------------------------------------------------------------ 3D layer instances
+
+/// A red triangle in the Z = 0 plane (the engine instance3d tests' glTF, buffer embedded as a
+/// data URI), parsed in memory: a FootageSource that knows one model item.
+const TRIANGLE: &str = r#"{
+  "asset": {"version": "2.0"},
+  "scenes": [{"nodes": [0]}],
+  "nodes": [{"mesh": 0}],
+  "meshes": [{"primitives": [{"attributes": {"POSITION": 0, "NORMAL": 1}, "material": 0}]}],
+  "materials": [{"pbrMetallicRoughness": {"baseColorFactor": [1.0, 0.0, 0.0, 1.0]}}],
+  "buffers": [{"byteLength": 72, "uri": "data:application/octet-stream;base64,AACAvwAAgL8AAAAAAACAPwAAgL8AAAAAAAAAAAAAgD8AAAAAAAAAAAAAAAAAAIA/AAAAAAAAAAAAAIA/AAAAAAAAAAAAAIA/"}],
+  "bufferViews": [
+    {"buffer": 0, "byteOffset": 0, "byteLength": 36},
+    {"buffer": 0, "byteOffset": 36, "byteLength": 36}
+  ],
+  "accessors": [
+    {"bufferView": 0, "componentType": 5126, "type": "VEC3", "count": 3, "min": [-1.0, -1.0, 0.0], "max": [1.0, 1.0, 0.0]},
+    {"bufferView": 1, "componentType": 5126, "type": "VEC3", "count": 3}
+  ]
+}"#;
+
+struct SoloModels;
+
+impl crate::FootageSource for SoloModels {
+    fn frame(&self, _: ItemId, _: &effectcraft_project::Footage, _: Tick) -> Option<std::sync::Arc<crate::Image>> {
+        None
+    }
+    fn model(&self, _: ItemId, f: &effectcraft_project::Footage) -> Option<std::sync::Arc<effectcraft_model::Model>> {
+        effectcraft_model::load(&f.path, TRIANGLE.as_bytes(), &|_| None).ok().map(std::sync::Arc::new)
+    }
+}
+
+/// A red triangle 3D model, a camera panned right by `pan` px and, on top of the stack, the
+/// copy: a solid with a 3D Layer Instance effect referencing the model.
+fn instance_scene(pan: f64) -> (Project, ItemId) {
+    let (mut p, cid, comp) = setup();
+    // Models are Advanced 3D (layer.newModel switches a Classic comp over).
+    p.comp_mut(cid).unwrap().renderer = effectcraft_project::Renderer::Advanced3D;
+    let mid = p.add_item(
+        "Triangle",
+        Label::Red,
+        None,
+        ItemKind::Footage(effectcraft_project::Footage {
+            path: "Triangle.gltf".into(),
+            kind: effectcraft_project::FootageKind::Model,
+            frame_rate: FrameRate::FPS_30,
+            codec: "glTF".into(),
+            ..Default::default()
+        }),
+    );
+    let model = build::layer(&mut p, &comp, "Triangle", LayerSource::Model { item: mid }, (200, 100), None);
+    let mut cam = build::layer(&mut p, &comp, "Camera", LayerSource::Camera, (200, 100), None);
+    for path in ["transform/position", "transform/poi"] {
+        let pr = cam.props.prop_mut(path).unwrap();
+        let Value::Vec3(v) = pr.value else { panic!("{path}: {:?}", pr.value) };
+        pr.value = Value::Vec3([v[0] + pan, v[1], v[2]]);
+    }
+    let mut owner = solid(&mut p, &comp, [1.0, 1.0, 1.0], 200, 100);
+    add_effect_200(&mut p, &mut owner, "ec.3d.instance3d", &[("layer", Value::Layer(Some(model.id.0)))]);
+    p.comp_mut(cid).unwrap().layers = vec![cam, owner, model];
+    (p, cid)
+}
+
+fn render_models(p: &Project, cid: ItemId, t: Tick, cache: Option<&crate::LayerCache>) -> crate::Image {
+    let mut r = crate::Renderer::new(p, &SoloModels, crate::RenderOpts::default());
+    r.cache = cache;
+    r.comp_frame(cid, t)
+}
+
+/// The coverage-weighted centre of the triangle (x): where its drawn pixels are, lit or not.
+fn cover_x(img: &crate::Image) -> f32 {
+    let (mut m, mut sx) = (0.0, 0.0);
+    for y in 0..img.height {
+        for x in 0..img.width {
+            let a = img.get(x as i64, y as i64)[3];
+            m += a;
+            sx += a * x as f32;
+        }
+    }
+    assert!(m > 1.0, "the triangle is drawn");
+    sx / m
+}
+
+/// Create 3D Layer Instance: the copy (the owner) is cached, and its key covers what the
+/// referenced model's solo render depends on — the camera, and the model's in/out gate.
+#[test]
+fn an_instance_of_a_model_is_cached_and_follows_the_camera() {
+    let t = Tick::from_seconds_f64(1.0);
+    let (p, cid) = instance_scene(0.0);
+    let (q, _) = instance_scene(40.0);
+    let key_at = |p: &Project, t: Tick| {
+        let c = p.comp(cid).unwrap();
+        crate::cache::layer_key(&crate::EvalCtx::new(p, cid, c, t), &c.layers[1], 1.0, false, false).unwrap()
+    };
+    assert_ne!(key_at(&p, t), key_at(&q, t), "moving the camera changes the copy's key");
+    // The same layer at a later time, outside its in/out range: the read turns transparent.
+    let mut out = p.clone();
+    out.comp_mut(cid).unwrap().layers[2].out_point = Tick::from_seconds_f64(0.5);
+    assert_ne!(key_at(&out, Tick::from_seconds_f64(0.25)), key_at(&out, t), "leaving the model's in/out range changes the copy's key");
+    // Two renders of one time: the second is served from the cache.
+    let cache = crate::LayerCache::default();
+    let here = render_models(&p, cid, t, Some(&cache));
+    let again = render_models(&p, cid, t, Some(&cache));
+    assert_same(&again, &render_models(&p, cid, t, None), "the second render is the cached one");
+    assert!(cache.stats().hits > 0, "the copy was served from the cache");
+    // Panning the camera: the copy (and the model) move with it.
+    let panned = render_models(&q, cid, t, Some(&cache));
+    assert_same(&panned, &render_models(&q, cid, t, None), "cached render after the camera moved");
+    let (a, b) = (cover_x(&here), cover_x(&panned));
+    assert!(b < a - 20.0, "panning the camera right moves the copy left: {a} -> {b}");
+}
+
+/// The camera's depth of field blurs the solo render (focus, aperture, iris, highlights) —
+/// none of it is in the projection matrix: changing any of it must change the copy's key, or
+/// it would serve the un-blurred pixels.
+#[test]
+fn the_copy_key_covers_the_cameras_depth_of_field() {
+    let t = Tick::from_seconds_f64(1.0);
+    let (p, cid) = instance_scene(0.0);
+    let set_dof = |p: &Project, on: bool, focus: f64, aperture: f64| {
+        let mut q = p.clone();
+        let cam = &mut q.comp_mut(cid).unwrap().layers[0];
+        for (path, v) in
+            [("cameraOptions/dof", Value::Bool(on)), ("cameraOptions/focusDistance", Value::Scalar(focus)), ("cameraOptions/aperture", Value::Scalar(aperture))]
+        {
+            cam.props.prop_mut(path).unwrap().value = v;
+        }
+        q
+    };
+    let key_at = |p: &Project| {
+        let c = p.comp(cid).unwrap();
+        crate::cache::layer_key(&crate::EvalCtx::new(p, cid, c, t), &c.layers[1], 1.0, false, false).unwrap()
+    };
+    let ka = key_at(&set_dof(&p, true, 500.0, 20.0));
+    let kb = key_at(&set_dof(&p, true, 500.0, 40.0)); // aperture
+    let kc = key_at(&set_dof(&p, true, 700.0, 20.0)); // focus
+    let kd = key_at(&set_dof(&p, false, 500.0, 20.0)); // the switch off
+    assert!(ka != kb && ka != kc && ka != kd && kb != kc, "aperture, focus and the switch each change the key");
+}
+
+/// A model with an animation clip selected is posed at its layer time: every time is its own
+/// entry. Without one (the default) the pose is the same at every time: one key inside the
+/// in/out range, as before.
+#[test]
+fn the_copy_key_covers_an_animated_models_layer_time() {
+    let (p, cid) = instance_scene(0.0);
+    let (t0, t1) = (Tick::from_seconds_f64(0.5), Tick::from_seconds_f64(1.0));
+    let key_at = |p: &Project, t: Tick| {
+        let c = p.comp(cid).unwrap();
+        crate::cache::layer_key(&crate::EvalCtx::new(p, cid, c, t), &c.layers[1], 1.0, false, false).unwrap()
+    };
+    assert_eq!(key_at(&p, t0), key_at(&p, t1), "a model without a clip keeps one key across times");
+    let mut q = p.clone();
+    q.comp_mut(cid).unwrap().layers[2].props.prop_mut("geometryOptions/animation").unwrap().value = Value::Enum(1);
+    assert_ne!(key_at(&q, t0), key_at(&q, t1), "an animated model's key follows its layer time");
+    // Two times and back: each is rendered fresh, none served another time's pixels.
+    let cache = crate::LayerCache::default();
+    let first = render_models(&q, cid, t0, Some(&cache));
+    let second = render_models(&q, cid, t1, Some(&cache));
+    assert_eq!(cache.stats().hits, 0, "the second time is not served the first time's pixels");
+    assert_same(&second, &render_models(&q, cid, t1, None), "the second time is a fresh render");
+    let again = render_models(&q, cid, t0, Some(&cache));
+    assert_eq!(cache.stats().hits, 1, "the first time is served on the way back");
+    assert_same(&again, &first, "the way back is the first time's pixels");
+}
+
+/// An Environment light's image lights Advanced 3D models — its source can be any layer's
+/// render: with one on, the read is not cached, so changes to it cannot reuse stale pixels.
+#[test]
+fn an_environment_light_makes_the_copy_uncached() {
+    let (p, cid) = instance_scene(0.0);
+    let mut q = p.clone();
+    let comp = q.comp(cid).unwrap().clone();
+    let env = build::layer(&mut q, &comp, "Env", LayerSource::Light { kind: effectcraft_project::LightKind::Environment }, (200, 100), None);
+    q.comp_mut(cid).unwrap().layers.insert(0, env);
+    let t = Tick::from_seconds_f64(1.0);
+    let key_at = |p: &Project| {
+        let c = p.comp(cid).unwrap();
+        crate::cache::layer_key(&crate::EvalCtx::new(p, cid, c, t), &c.layers[2], 1.0, false, false)
+    };
+    assert!(key_at(&q).is_none(), "with an Environment light the read is not cached");
+    let cache = crate::LayerCache::default();
+    let a = render_models(&q, cid, t, Some(&cache));
+    let b = render_models(&q, cid, t, Some(&cache));
+    assert_same(&a, &b, "two fresh renders agree");
+    assert_eq!(cache.stats().hits, 0, "nothing is served from the cache");
+    // The light off (not lighting): the cache comes back.
+    q.comp_mut(cid).unwrap().layers[0].switches.video = false;
+    assert!(key_at(&q).is_some(), "the light off, the read is cached again");
+}

crates/render/src/tests/audio_fx.rs

@@ -2,7 +2,7 @@
 
 use std::sync::Arc;
 
-use effectcraft_keyframe::Value;
+use effectcraft_keyframe::{Keyframe, Value};
 use effectcraft_project::build::{self, Ids};
 use effectcraft_project::{Comp, Footage, FootageKind, ItemId, ItemKind, LayerSource, Project, Solid};
 use effectcraft_time::{FrameRate, Tick};
@@ -148,6 +148,42 @@ fn stereo_mixer_pans() {
     assert!(m.chunks(2).all(|f| f[0].abs() < 1e-6 && (f[1] - 0.5).abs() < 1e-6), "{:?}", &m[..4]);
 }
 
+/// Key `prop` of layer 0 (`effect`: in its first effect, else in Audio) from `a` at 0 s to `b` at 1 s.
+fn key(p: &mut Project, cid: ItemId, effect: bool, prop: &str, a: Value, b: Value) {
+    let l = &mut p.comp_mut(cid).unwrap().layers[0];
+    let g = if effect { l.props.sub_mut("effects").unwrap().children[0].as_group_mut().unwrap() } else { l.props.sub_mut("audio").unwrap() };
+    g.get_mut(prop).unwrap().keys = vec![Keyframe::new(Tick::ZERO, a), Keyframe::new(Tick::from_seconds_f64(1.0), b)];
+}
+
+/// Left samples of a mix of constant 0.5 audio over the layer's 1 s, in blocks of `block` samples.
+fn left_ramp(p: &Project, cid: ItemId, block: usize) -> Vec<f32> {
+    fn half(_: f64) -> (f32, f32) {
+        (0.5, 0.5)
+    }
+    let mut m = vec![];
+    for k in 0..SR as usize / block {
+        m.extend(mix(p, &Signal(half), cid, (k * block) as f64 / SR as f64, block));
+    }
+    m.iter().step_by(2).copied().collect()
+}
+
+/// Keyframed Audio Levels and Stereo Mixer levels ramp smoothly inside a block (export mixes one
+/// second at a time), instead of holding the value at the block's first sample.
+#[test]
+fn animated_levels_ramp_within_a_block() {
+    let (mut levels, lc) = comp_with(None, &[], false);
+    key(&mut levels, lc, false, "levels", Value::Vec2([-60.0, -60.0]), Value::Vec2([0.0, 0.0]));
+    let (mut mixer, mc) = comp_with(Some("ec.audio.stereomixer"), &[], false);
+    key(&mut mixer, mc, true, "leftLevel", Value::Scalar(0.0), Value::Scalar(100.0));
+    for (name, p, cid, mid) in [("levels", &levels, lc, 0.5 * 10f32.powf(-1.5)), ("stereo mixer", &mixer, mc, 0.25)] {
+        let one = left_ramp(p, cid, SR as usize);
+        assert!(one.windows(2).all(|w| w[1] >= w[0]), "{name}: not monotonic");
+        assert!(one[100] < one[4000] && one[4000] < one[7900], "{name}: {} {} {}", one[100], one[4000], one[7900]);
+        assert!((one[4000] / mid - 1.0).abs() < 0.05, "{name}: {} at 0.5 s, want {mid}", one[4000]);
+        assert_eq!(one, left_ramp(p, cid, 320), "{name}: block size changes the result");
+    }
+}
+
 #[test]
 fn tone_makes_a_solid_audible_at_its_frequency() {
     let mut vals: Vec<(&str, Value)> = vec![("frequency1", Value::Scalar(500.0))];

crates/render/src/tests/collapse.rs

@@ -3,7 +3,7 @@
 use effectcraft_color::{BlendMode, Label};
 use effectcraft_keyframe::{TextDoc, Value};
 use effectcraft_project::build::{self, Ids};
-use effectcraft_project::{BitDepth, Comp, ItemId, ItemKind, Layer, LayerSource, Project, Quality, Solid};
+use effectcraft_project::{BitDepth, Comp, FrameBlend, ItemId, ItemKind, Layer, LayerSource, Project, Quality, Solid};
 use effectcraft_time::{FrameRate, Tick};
 
 use crate::{EvalCtx, Image, NoFootage, RenderOpts, Renderer, render_frame};
@@ -110,6 +110,66 @@ fn masks_on_a_collapsed_layer_force_a_flattened_render() {
     assert!(max_diff(&a, &b) < 1e-4, "{}", max_diff(&a, &b));
 }
 
+/// #1747: the flattened path honours a composition proxy and frame blending; a collapsed layer
+/// renders the nested comp directly and ignores both, so such a layer must not collapse.
+#[test]
+fn proxy_and_frame_blending_keep_a_precomp_on_the_flattened_path() {
+    let (mut p, cid) = scene(true, false);
+    let id = p.comp(cid).unwrap().layers[0].id;
+    let collapses = |p: &Project| {
+        let r = Renderer::new(p, &NoFootage, RenderOpts::default());
+        let ctx = EvalCtx::new(p, cid, p.comp(cid).unwrap(), Tick::ZERO);
+        r.collapsed(&ctx, ctx.comp.layer(id).unwrap()).is_some()
+    };
+    assert!(collapses(&p), "a plain precomp collapses");
+    // Frame blending needs both the comp's switch and the layer's.
+    p.comp_mut(cid).unwrap().enable_frame_blending = true;
+    p.comp_mut(cid).unwrap().layers[0].switches.frame_blend = FrameBlend::FrameMix;
+    assert!(!collapses(&p), "frame blending keeps the flattened path");
+    p.comp_mut(cid).unwrap().enable_frame_blending = false;
+    p.comp_mut(cid).unwrap().layers[0].switches.frame_blend = FrameBlend::Off;
+    // A composition proxy stands in for the precomp's pixels.
+    let LayerSource::Comp { item } = p.comp(cid).unwrap().layers[0].source else { panic!("a precomp layer") };
+    let proxy =
+        effectcraft_project::Proxy { footage: effectcraft_project::Footage { has_video: true, width: 32, height: 32, ..Default::default() }, enabled: true };
+    p.item_mut(item).unwrap().proxy = Some(Box::new(proxy));
+    assert!(!collapses(&p), "a proxy keeps the flattened path");
+}
+
+/// #1747: an effect on B that reads A must not reuse its cached buffer when two collapsed
+/// instances give A different static overrides (`hash_values` only sees animated values).
+#[test]
+fn referenced_layer_overrides_change_the_owner_cache_key() {
+    let mut p = project();
+    let comp = Comp::new(100, 100, FrameRate::FPS_30, Tick::from_seconds_f64(2.0));
+    let a = solid(&mut p, &comp, [1.0, 1.0, 1.0], (40, 40), [30.0, 50.0, 0.0]);
+    let aid = a.id;
+    let mut b = solid(&mut p, &comp, [1.0, 1.0, 1.0], (100, 100), [50.0, 50.0, 0.0]);
+    let bid = b.id;
+    let mut next = p.next_id;
+    let mut ids = Ids(&mut next);
+    let spec = effectcraft_effects::find("ec.channel.setmatte").unwrap();
+    let mut fx = effectcraft_effects::instantiate(spec, &mut ids, spec.name, [100.0, 100.0]);
+    fx.prop_mut("takeMatteFromLayer").unwrap().value = Value::Layer(Some(a.id.0));
+    p.next_id = next;
+    b.props.sub_mut("effects").unwrap().children.push(fx.into());
+    let mut c = comp;
+    c.layers = vec![b, a];
+    let cid = p.add_item("Comp", Label::Sandstone, None, ItemKind::Comp(c.into()));
+    let comp = p.comp(cid).unwrap();
+    let b = comp.layer(bid).unwrap();
+    let opacity = comp.layer(aid).unwrap().props.prop("transform/opacity").unwrap().uid;
+    let key = |value: f64| {
+        let overrides = [crate::PropertyOverride { layer: aid, prop: opacity, value: Value::Scalar(value), font: false }];
+        let ctx =
+            EvalCtx { project: &p, comp_id: cid, comp, time: Tick::ZERO, expr: None, footage: None, property_overrides: &overrides, media_overrides: &[] };
+        crate::cache::layer_key(&ctx, b, 1.0, false, false)
+    };
+    let (opaque, half) = (key(100.0), key(50.0));
+    assert!(opaque.is_some(), "the owner is cacheable");
+    assert_ne!(opaque, half, "A's static override changes B's key");
+}
+
 #[test]
 fn collapsed_3d_layers_join_the_parent_scene() {
     // Parent: a red 3D solid at z = 0 above (in the stack) a collapsed 3D precomp holding a

crates/render/src/tests/time.rs

@@ -134,7 +134,16 @@ fn input_keys_ignore_later_effects() {
     }
     let key = |p: &Project| {
         let comp = p.comp(cid).unwrap();
-        let ctx = crate::EvalCtx { project: p, comp_id: cid, comp, time: Tick::from_seconds_f64(0.5), expr: None, footage: None };
+        let ctx = crate::EvalCtx {
+            project: p,
+            comp_id: cid,
+            comp,
+            time: Tick::from_seconds_f64(0.5),
+            expr: None,
+            footage: None,
+            property_overrides: &[],
+            media_overrides: &[],
+        };
         let l = &comp.layers[0];
         (crate::cache::input_key(&ctx, l, 1.0, false, false, 1), crate::cache::input_key(&ctx, l, 1.0, false, false, 2))
     };

crates/render/src/three_d/adv/scene.rs

@@ -857,8 +857,8 @@ fn emit_layer<'a>(r: &Renderer<'a>, ctx: &EvalCtx<'a>, layer: &Layer, b: &mut Bu
     if layer.environment || layer.switches.adjustment || ctx.opacity(layer) <= 0.0 || !layer.has_video() {
         return;
     }
-    if let Some(item) = r.collapsed(ctx, layer) {
-        collapsed_layer(r, ctx, layer, item, b);
+    if let Some(collapsed) = r.collapsed(ctx, layer) {
+        collapsed_layer(r, ctx, layer, &collapsed, b);
     } else if layer.source.is_model() {
         model_layer(r, ctx, layer, b);
     } else if matches!(layer.source, LayerSource::Text | LayerSource::Shape)
@@ -874,9 +874,9 @@ fn emit_layer<'a>(r: &Renderer<'a>, ctx: &EvalCtx<'a>, layer: &Layer, b: &mut Bu
 /// (meshes, extrusions, cards) placed by the precomp layer's world transform, so they
 /// intersect, occlude and shadow the parent's layers. Nested 2D layers lie on the precomp
 /// layer's plane; nested lights and cameras are ignored (the parent's light the scene).
-fn collapsed_layer<'a>(r: &Renderer<'a>, ctx: &EvalCtx<'a>, layer: &Layer, item: effectcraft_project::ItemId, b: &mut Builder) {
+fn collapsed_layer<'a>(r: &Renderer<'a>, ctx: &EvalCtx<'a>, layer: &Layer, collapsed: &crate::Collapsed, b: &mut Builder) {
     let op = ctx.opacity(layer) as f32 * r.opacity_mul();
-    let Some((sub, nctx)) = r.collapse_into(ctx, layer, item, op) else { return };
+    let Some((sub, nctx)) = r.collapse_into(ctx, layer, collapsed, op) else { return };
     let saved = b.outer;
     b.outer = saved * ctx.world_matrix(layer);
     let t = nctx.time;

crates/render/src/three_d/adv/tests.rs

@@ -370,7 +370,16 @@ fn extruded_text_renders_as_a_mesh() {
         set(l, "geometryOptions/bevelStyle", Value::Enum(1));
         set(l, "transform/rotationY", Value::Scalar(40.0));
     });
-    let ctx = crate::EvalCtx { project: &p, comp_id: cid, comp: p.comp(cid).unwrap(), time: Tick::ZERO, expr: None, footage: None };
+    let ctx = crate::EvalCtx {
+        project: &p,
+        comp_id: cid,
+        comp: p.comp(cid).unwrap(),
+        time: Tick::ZERO,
+        expr: None,
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let l = &ctx.comp.layers[0];
     let params = scene::extrusion_params(&ctx, l).unwrap();
     let meshes = scene::extruded_meshes(&ctx, l, &params);
@@ -409,7 +418,16 @@ fn shape_surface_items_colour_the_extruded_surfaces() {
         set(l, "geometryOptions/extrusionDepth", Value::Scalar(40.0));
         set(l, "transform/position", Value::Vec3([100.0, 100.0, 0.0]));
     });
-    let ctx = crate::EvalCtx { project: &p, comp_id: cid, comp: p.comp(cid).unwrap(), time: Tick::ZERO, expr: None, footage: None };
+    let ctx = crate::EvalCtx {
+        project: &p,
+        comp_id: cid,
+        comp: p.comp(cid).unwrap(),
+        time: Tick::ZERO,
+        expr: None,
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let l = &ctx.comp.layers[0];
     let params = scene::extrusion_params(&ctx, l).unwrap();
     let meshes = scene::extruded_meshes(&ctx, l, &params);
@@ -445,7 +463,16 @@ fn text_animators_colour_the_extruded_surfaces() {
         set(l, "geometryOptions/extrusionDepth", Value::Scalar(30.0));
         set(l, "geometryOptions/bevelStyle", Value::Enum(1));
     });
-    let ctx = crate::EvalCtx { project: &p, comp_id: cid, comp: p.comp(cid).unwrap(), time: Tick::ZERO, expr: None, footage: None };
+    let ctx = crate::EvalCtx {
+        project: &p,
+        comp_id: cid,
+        comp: p.comp(cid).unwrap(),
+        time: Tick::ZERO,
+        expr: None,
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let l = &ctx.comp.layers[0];
     let params = scene::extrusion_params(&ctx, l).unwrap();
     let meshes = scene::extruded_meshes(&ctx, l, &params);
@@ -643,7 +670,16 @@ fn extruded_strokes_render_as_bevelled_meshes() {
         set(l, "geometryOptions/extrusionDepth", Value::Scalar(20.0));
         set(l, "geometryOptions/bevelStyle", Value::Enum(1));
     });
-    let ctx = crate::EvalCtx { project: &p, comp_id: cid, comp: p.comp(cid).unwrap(), time: Tick::ZERO, expr: None, footage: None };
+    let ctx = crate::EvalCtx {
+        project: &p,
+        comp_id: cid,
+        comp: p.comp(cid).unwrap(),
+        time: Tick::ZERO,
+        expr: None,
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let l = &ctx.comp.layers[0];
     let params = scene::extrusion_params(&ctx, l).unwrap();
     let meshes = scene::extruded_meshes(&ctx, l, &params);

crates/render/src/three_d/bokeh.rs

@@ -289,16 +289,24 @@ pub fn progressive_blur(img: &Image, iris: &Iris, radius: &[f32]) -> Image {
         return bokeh_blur(img, iris, levels[0] as f64);
     }
     let (lo, hi, n) = (levels[0], levels[levels.len() - 1], levels.len());
-    let blurred: Vec<Image> = levels.par_iter().map(|&r| bokeh_blur(img, iris, r as f64)).collect();
+    // A pixel blends only the two levels around its radius, so the levels are made in order and
+    // only that pair is held: peak memory stays a few images whatever the level count, rather
+    // than one image per level. Each level's blur is parallel over its rows.
     let mut out = Image::new(img.width, img.height);
-    out.data.par_iter_mut().enumerate().for_each(|(i, o)| {
-        let r = radius[i];
-        let f = ((r - lo) / (hi - lo) * (n - 1) as f32).clamp(0.0, (n - 1) as f32);
-        let k = (f.floor() as usize).min(n - 2);
-        let t = f - k as f32;
-        let (a, b) = (blurred[k].data[i], blurred[k + 1].data[i]);
-        *o = [0, 1, 2, 3].map(|c| a[c] + (b[c] - a[c]) * t);
-    });
+    let mut below = bokeh_blur(img, iris, lo as f64);
+    for (k, &r) in levels.iter().enumerate().skip(1) {
+        let above = bokeh_blur(img, iris, r as f64);
+        out.data.par_iter_mut().enumerate().for_each(|(i, o)| {
+            let f = ((radius[i] - lo) / (hi - lo) * (n - 1) as f32).clamp(0.0, (n - 1) as f32);
+            let kk = (f.floor() as usize).min(n - 2);
+            if kk + 1 == k {
+                let t = f - kk as f32;
+                let (a, b) = (below.data[i], above.data[i]);
+                *o = [0, 1, 2, 3].map(|c| a[c] + (b[c] - a[c]) * t);
+            }
+        });
+        below = above;
+    }
     out
 }
 

crates/render/src/three_d/camera.rs

@@ -37,7 +37,8 @@ pub struct Dof {
 impl Dof {
     /// Circle-of-confusion diameter (comp pixels) for a point at camera depth `z`.
     pub fn coc(&self, z: f64) -> f64 {
-        if z <= NEAR || self.focus <= 0.0 {
+        // No defocus can be measured against a non-finite focus or depth, so it counts as in focus.
+        if !z.is_finite() || z <= NEAR || !self.focus.is_finite() || self.focus <= 0.0 {
             return 0.0;
         }
         self.aperture * (z - self.focus).abs() / z * self.blur_level
@@ -360,22 +361,27 @@ pub fn layer_camera(ctx: &EvalCtx, cam: &Layer) -> CameraState {
     let (eye, fwd, down) = layer_frame(ctx, cam);
     let opts = cam.props.sub("cameraOptions");
     let zoom = opts.map(|g| ctx.f(cam, g, "zoom", 1000.0)).unwrap_or(1000.0).max(1e-3);
-    let dof = opts.filter(|g| ctx.b(cam, g, "dof")).map(|g| Dof {
-        focus: ctx.f(cam, g, "focusDistance", zoom),
-        aperture: ctx.f(cam, g, "aperture", default_aperture(w)).max(0.0),
-        blur_level: ctx.f(cam, g, "blurLevel", 100.0).max(0.0) / 100.0,
-        iris: super::bokeh::Iris {
-            sides: super::bokeh::Iris::sides_of_shape(ctx.e(cam, g, "irisShape")),
-            rotation: ctx.f(cam, g, "irisRotation", 0.0),
-            roundness: ctx.f(cam, g, "irisRoundness", 0.0) / 100.0,
-            aspect: ctx.f(cam, g, "irisAspectRatio", 1.0).max(0.01),
-            fringe: ctx.f(cam, g, "irisDiffractionFringe", 0.0).max(0.0) / 100.0,
-        },
-        highlight: super::bokeh::Highlight {
-            gain: ctx.f(cam, g, "highlightGain", 0.0).clamp(0.0, 100.0) / 100.0,
-            threshold: ctx.f(cam, g, "highlightThreshold", 255.0).clamp(0.0, 255.0) / 255.0,
-            saturation: ctx.f(cam, g, "highlightSaturation", 0.0).clamp(0.0, 100.0) / 100.0,
-        },
+    let dof = opts.filter(|g| ctx.b(cam, g, "dof")).map(|g| {
+        // A non-finite Focus Distance would make every blur radius non-finite; use the value the
+        // property defaults to (the zoom plane) instead.
+        let focus = ctx.f(cam, g, "focusDistance", zoom);
+        Dof {
+            focus: if focus.is_finite() { focus } else { zoom },
+            aperture: ctx.f(cam, g, "aperture", default_aperture(w)).max(0.0),
+            blur_level: ctx.f(cam, g, "blurLevel", 100.0).max(0.0) / 100.0,
+            iris: super::bokeh::Iris {
+                sides: super::bokeh::Iris::sides_of_shape(ctx.e(cam, g, "irisShape")),
+                rotation: ctx.f(cam, g, "irisRotation", 0.0),
+                roundness: ctx.f(cam, g, "irisRoundness", 0.0) / 100.0,
+                aspect: ctx.f(cam, g, "irisAspectRatio", 1.0).max(0.01),
+                fringe: ctx.f(cam, g, "irisDiffractionFringe", 0.0).max(0.0) / 100.0,
+            },
+            highlight: super::bokeh::Highlight {
+                gain: ctx.f(cam, g, "highlightGain", 0.0).clamp(0.0, 100.0) / 100.0,
+                threshold: ctx.f(cam, g, "highlightThreshold", 255.0).clamp(0.0, 255.0) / 255.0,
+                saturation: ctx.f(cam, g, "highlightSaturation", 0.0).clamp(0.0, 100.0) / 100.0,
+            },
+        }
     });
     CameraState { view: basis_view(eye, fwd, down), eye, zoom, ortho: false, dof }
 }

crates/render/src/three_d/compose.rs

@@ -18,7 +18,7 @@ use std::sync::Arc;
 use effectcraft_color::{BlendMode, blend_pixel};
 use effectcraft_effects::Buf;
 use effectcraft_geom::{Mat3, Mat4, Vec3, vec3};
-use effectcraft_project::{Layer, LightKind, MatteKind};
+use effectcraft_project::{Layer, LightKind, MatteKind, limits};
 use effectcraft_raster::{Image, Px, hash_noise};
 use effectcraft_time::Tick;
 use rayon::prelude::*;
@@ -195,13 +195,13 @@ fn mb_samples(r: &Renderer, ctx: &EvalCtx, layer: &Layer) -> usize {
 }
 
 /// Prepare a layer (buffer, geometry, material). `None` when it shows nothing.
-pub(crate) fn prepare<'a>(r: &Renderer, ctx: &EvalCtx<'a>, layer: &'a Layer, order: usize, out: (u32, u32), in_run: bool) -> Option<Item<'a>> {
+pub(crate) fn prepare<'a>(r: &Renderer, ctx: &EvalCtx<'_>, layer: &'a Layer, order: usize, out: (u32, u32), in_run: bool) -> Option<Item<'a>> {
     let buf = r.blend_layer_buf(ctx, layer)?;
     prepare_with(r, ctx, layer, order, out, in_run, PlaneInput { buf, local: Mat4::IDENTITY })
 }
 
 /// Prepare a layer as planes: one per character for per-character 3D text, else one.
-pub(crate) fn prepare_all<'a>(r: &Renderer, ctx: &EvalCtx<'a>, layer: &'a Layer, order: usize, out: (u32, u32), in_run: bool) -> Vec<Item<'a>> {
+pub(crate) fn prepare_all<'a>(r: &Renderer, ctx: &EvalCtx<'_>, layer: &'a Layer, order: usize, out: (u32, u32), in_run: bool) -> Vec<Item<'a>> {
     if crate::text::per_char_3d(ctx, layer) {
         return crate::text::per_char_planes(ctx, layer, r.opts.scale)
             .into_iter()
@@ -218,7 +218,7 @@ struct PlaneInput {
 }
 
 /// Prepare the plane's geometry, motion samples and material.
-fn prepare_with<'a>(r: &Renderer, ctx: &EvalCtx<'a>, layer: &'a Layer, order: usize, out: (u32, u32), in_run: bool, plane: PlaneInput) -> Option<Item<'a>> {
+fn prepare_with<'a>(r: &Renderer, ctx: &EvalCtx<'_>, layer: &'a Layer, order: usize, out: (u32, u32), in_run: bool, plane: PlaneInput) -> Option<Item<'a>> {
     let PlaneInput { mut buf, local } = plane;
     if buf.img.is_empty() {
         return None;
@@ -287,12 +287,45 @@ fn prepare_with<'a>(r: &Renderer, ctx: &EvalCtx<'a>, layer: &'a Layer, order: us
 }
 
 /// Blur radius (buffer pixels) of every buffer pixel of a plane at `world` (layer → world), from
-/// its camera depth: the circle of confusion over the on-screen size of one layer pixel there.
-fn dof_radii(cam: &CameraState, dof: &super::camera::Dof, world: Mat4, buf: &Buf) -> Vec<f32> {
-    dof_radii_at(cam, dof, world, (buf.img.width as usize, buf.img.height as usize), buf.offset, buf.scale)
+/// its camera depth: the circle of confusion over the on-screen size of one layer pixel there, at
+/// most `cap` ([`dof_radius_cap`]).
+fn dof_radii(cam: &CameraState, dof: &super::camera::Dof, world: Mat4, buf: &Buf, cap: f64) -> Vec<f32> {
+    dof_radii_at(cam, dof, world, (buf.img.width as usize, buf.img.height as usize), buf.offset, buf.scale, cap)
 }
 
-fn dof_radii_at(cam: &CameraState, dof: &super::camera::Dof, world: Mat4, (w, h): (usize, usize), offset: [f64; 2], scale: f64) -> Vec<f32> {
+/// Pixels a padded blur buffer may have: the ~16 million layer buffers are held to
+/// ([`crate::Renderer::raster_scale`]), or twice the buffer when that is larger, so a big buffer
+/// can still be blurred. The blur holds a few images of this size at once whatever its level
+/// count ([`super::bokeh::progressive_blur`]), so blurring a small plane costs no more memory than
+/// blurring a large layer.
+const DOF_PAD_BUDGET: f64 = 16.0e6;
+
+/// Comp pixels per buffer pixel below which a plane isn't blurred. Such a plane covers almost no
+/// screen area (a 0%-scaled layer, one at an extreme distance), while its radius in buffer
+/// pixels grows without bound as it shrinks: blurring it would cost the most for the least.
+const DOF_MIN_SCREEN_SCALE: f64 = 1e-3;
+
+/// The largest blur radius (buffer pixels) of a `w`×`h` buffer: the one whose padded copy just
+/// fits [`DOF_PAD_BUDGET`]. The circle of confusion has no bound of its own (a focus distance far
+/// beyond the scene, a near-zero layer scale), so memory sets the limit; ordinary bokeh stays far
+/// below it and is never clamped.
+pub(super) fn dof_radius_cap(dof: &super::camera::Dof, w: u32, h: u32) -> f64 {
+    let (w, h) = (w as f64, h as f64);
+    let budget = DOF_PAD_BUDGET.max(2.0 * w * h);
+    // (w + 2p)·(h + 2p) = budget, solved for the padding p.
+    let pad = (((w - h) * (w - h) + 4.0 * budget).sqrt() - (w + h)) / 4.0;
+    ((pad - 2.0) / iris_stretch(dof)).max(0.0)
+}
+
+pub(super) fn dof_radii_at(
+    cam: &CameraState,
+    dof: &super::camera::Dof,
+    world: Mat4,
+    (w, h): (usize, usize),
+    offset: [f64; 2],
+    scale: f64,
+    cap: f64,
+) -> Vec<f32> {
     let s = scale.max(1e-9);
     let sx = world.apply_vec(vec3(1.0, 0.0, 0.0)).length().max(1e-9);
     let at = |x: f64, y: f64| cam.depth(world.apply(vec3((x - offset[0]) / s, (y - offset[1]) / s, 0.0)));
@@ -306,31 +339,48 @@ fn dof_radii_at(cam: &CameraState, dof: &super::camera::Dof, world: Mat4, (w, h)
             if z <= super::camera::NEAR {
                 continue;
             }
-            // coc · ½ / (zoom / z · sx) · scale
-            *o = (dof.coc(z) * 0.5 * z / (cam.zoom * sx) * s) as f32;
+            // coc · ½ / (zoom / z · sx) · scale. Infinity clamps to the cap like any large radius,
+            // so the blur keeps growing with defocus; only NaN, which has no defocus, stays sharp.
+            let r = dof.coc(z) * 0.5 * z / (cam.zoom * sx) * s;
+            *o = if r.is_nan() || cam.zoom * sx / (z * s) < DOF_MIN_SCREEN_SCALE { 0.0 } else { r.min(cap) as f32 };
         }
     });
     out
 }
 
+/// How much the iris' aspect ratio stretches a blur radius along its longer axis.
+fn iris_stretch(dof: &super::camera::Dof) -> f64 {
+    let a = dof.iris.aspect.clamp(0.01, 100.0).sqrt();
+    a.max(1.0 / a)
+}
+
 /// The padding [`dof_blur`] gives a buffer whose largest blur radius is `rmax`.
 fn dof_pad(dof: &super::camera::Dof, rmax: f64) -> u32 {
-    let a = dof.iris.aspect.clamp(0.01, 100.0).sqrt().max(1.0 / dof.iris.aspect.clamp(0.01, 100.0).sqrt());
-    (rmax * a).ceil() as u32 + 2
+    ((rmax * iris_stretch(dof)).ceil() as u32).saturating_add(2)
+}
+
+/// The size of `img` padded by `pad` on every side, or `None` past [`limits::MAX_SIZE`] on a side:
+/// [`DOF_PAD_BUDGET`] bounds the area, so a long thin buffer could still outgrow a side.
+fn padded_size(img: &Image, pad: u32) -> Option<(u32, u32)> {
+    let grow = |n: u32| n.saturating_add(pad.saturating_mul(2));
+    let (w, h) = (grow(img.width), grow(img.height));
+    (w <= limits::MAX_SIZE && h <= limits::MAX_SIZE).then_some((w, h))
 }
 
 /// [`dof_blur`] planned for an accelerator: the padding, radius map and levels, and the padded
 /// buffer's layer-space bounds. `None` when nothing blurs.
 fn dof_plan(cam: &CameraState, dof: &super::camera::Dof, world: Mat4, buf: &Buf) -> Option<(PlaneDof, [f64; 4])> {
-    let radii = dof_radii(cam, dof, world, buf);
+    let cap = dof_radius_cap(dof, buf.img.width, buf.img.height);
+    let radii = dof_radii(cam, dof, world, buf, cap);
     let rmax = radii.iter().copied().fold(0.0f32, f32::max) as f64;
     if rmax <= 0.3 {
         return None;
     }
     let pad = dof_pad(dof, rmax);
-    let (w, h) = (buf.img.width as usize + 2 * pad as usize, buf.img.height as usize + 2 * pad as usize);
+    let (wp, hp) = padded_size(&buf.img, pad)?;
+    let (w, h) = (wp as usize, hp as usize);
     let offset = [buf.offset[0] + pad as f64, buf.offset[1] + pad as f64];
-    let radius = dof_radii_at(cam, dof, world, (w, h), offset, buf.scale);
+    let radius = dof_radii_at(cam, dof, world, (w, h), offset, buf.scale, cap);
     let levels = super::bokeh::blur_levels(&radius)?;
     let s = buf.scale.max(1e-9);
     let bounds = [-offset[0] / s, -offset[1] / s, (w as f64 - offset[0]) / s, (h as f64 - offset[1]) / s];
@@ -339,16 +389,20 @@ fn dof_plan(cam: &CameraState, dof: &super::camera::Dof, world: Mat4, buf: &Buf)
 
 /// Depth of field for one plane: highlights boosted, then a bokeh-shaped blur by depth.
 fn dof_blur(cam: &CameraState, dof: &super::camera::Dof, world: Mat4, buf: Arc<Buf>) -> Arc<Buf> {
-    let radii = dof_radii(cam, dof, world, &buf);
+    let cap = dof_radius_cap(dof, buf.img.width, buf.img.height);
+    let radii = dof_radii(cam, dof, world, &buf, cap);
     let rmax = radii.iter().copied().fold(0.0f32, f32::max) as f64;
     if rmax <= 0.3 {
         return buf;
     }
     let pad = dof_pad(dof, rmax);
+    if padded_size(&buf.img, pad).is_none() {
+        return buf;
+    }
     let mut padded = buf.img.padded(pad);
     super::bokeh::boost_highlights(&mut padded, &dof.highlight);
     let pbuf = Buf { img: padded, offset: [buf.offset[0] + pad as f64, buf.offset[1] + pad as f64], scale: buf.scale };
-    let pr = dof_radii(cam, dof, world, &pbuf);
+    let pr = dof_radii(cam, dof, world, &pbuf, cap);
     // The (cached, shared) layer buffer stays untouched; the blurred copy is per frame.
     Arc::new(Buf { img: super::bokeh::progressive_blur(&pbuf.img, &dof.iris, &pr), offset: pbuf.offset, scale: pbuf.scale })
 }
@@ -449,8 +503,8 @@ fn gather<'a>(r: &Renderer<'a>, ctx: &EvalCtx<'a>, run: &[&'a Layer], out: (u32,
         .flat_map_iter(|(i, l)| {
             // Stack order with room for a collapsed precomp's layers in between.
             let i = i * 1024;
-            if let Some(item) = r.collapsed(ctx, l) {
-                return collapsed_items(r, ctx, l, item, i, out);
+            if let Some(collapsed) = r.collapsed(ctx, l) {
+                return collapsed_items(r, ctx, l, &collapsed, i, out);
             }
             let mut its = prepare_all(r, ctx, l, i, out, true);
             if !its.is_empty() {
@@ -483,20 +537,13 @@ fn gather<'a>(r: &Renderer<'a>, ctx: &EvalCtx<'a>, run: &[&'a Layer], out: (u32,
 /// 3D space (world = precomp layer's world × nested world), depth-sorted with the run, so they
 /// intersect the parent's 3D layers; nested 2D layers lie on the precomp layer's plane in stack
 /// order. (Nested adjustment layers are skipped here.)
-fn collapsed_items<'a>(
-    r: &Renderer<'a>,
-    ctx: &EvalCtx<'a>,
-    layer: &'a Layer,
-    item: effectcraft_project::ItemId,
-    order: usize,
-    out: (u32, u32),
-) -> Vec<Item<'a>> {
+fn collapsed_items<'a>(r: &Renderer<'a>, ctx: &EvalCtx<'a>, layer: &'a Layer, collapsed: &crate::Collapsed, order: usize, out: (u32, u32)) -> Vec<Item<'a>> {
     let op = ctx.opacity(layer) as f32 * r.opacity_mul();
-    let Some((sub, nctx)) = r.collapse_into(ctx, layer, item, op) else { return vec![] };
+    let Some((sub, nctx)) = r.collapse_into(ctx, layer, collapsed, op) else { return vec![] };
     let t = nctx.time;
-    let any_solo = nctx.comp.any_solo();
-    let nested: Vec<&'a Layer> = nctx
-        .comp
+    let Some(nc) = r.project.comp(collapsed.item) else { return vec![] };
+    let any_solo = nc.any_solo();
+    let nested: Vec<&'a Layer> = nc
         .layers
         .iter()
         .rev()
@@ -863,7 +910,7 @@ pub(crate) fn aux_pass(r: &Renderer, ctx: &EvalCtx) -> effectcraft_raster::AuxCh
                     if nv[2] > 0.0 {
                         nv = nv.map(|v| -v);
                     }
-                    let (sw, sh) = crate::source_size(r.project, it.layer);
+                    let (sw, sh) = ctx.source_size(it.layer);
                     let size = if sw == 0 { [ctx.comp.width as f64, ctx.comp.height as f64] } else { [sw as f64, sh as f64] };
                     (number(it.layer), source_id(it.layer), crypto_hash(&it.layer.name), crypto_hash(&source_name(it.layer)), nv, size)
                 })

crates/render/src/three_d/tests.rs

@@ -13,10 +13,15 @@ const W: u32 = 200;
 const H: u32 = 100;
 
 fn setup() -> (Project, ItemId, Comp) {
+    setup_sized(W, H)
+}
+
+/// [`setup`] with a `w`×`h` comp.
+fn setup_sized(w: u32, h: u32) -> (Project, ItemId, Comp) {
     let mut p = Project::default();
     // Exact float maths; 8/16 bpc quantisation has its own tests (tests_color).
     p.settings.bit_depth = effectcraft_project::BitDepth::Bpc32;
-    let comp = Comp::new(W, H, FrameRate::FPS_30, Tick::from_seconds_f64(2.0));
+    let comp = Comp::new(w, h, FrameRate::FPS_30, Tick::from_seconds_f64(2.0));
     let cid = p.add_item("Comp", Label::Sandstone, None, ItemKind::Comp(comp.clone().into()));
     (p, cid, comp)
 }
@@ -374,7 +379,7 @@ fn shadow_diffusion_is_a_soft_ramp_not_copies() {
 // ---------------------------------------------------------------- cameras
 
 fn camera(p: &mut Project, comp: &Comp) -> Layer {
-    build::layer(p, comp, "Camera", LayerSource::Camera, (W, H), None)
+    build::layer(p, comp, "Camera", LayerSource::Camera, (comp.width, comp.height), None)
 }
 
 #[test]
@@ -450,9 +455,155 @@ fn depth_of_field_blurs_out_of_focus_layers() {
     assert!(b.get(66, 50)[3] > 0.01);
 }
 
+/// A non-finite Focus Distance doesn't reach the blur: the camera focuses on the property's
+/// default plane (`zoom`) instead.
+#[test]
+fn dof_falls_back_when_focus_distance_is_not_finite() {
+    for bad in [f64::NAN, f64::INFINITY, f64::NEG_INFINITY] {
+        let (mut p, cid, comp) = setup();
+        let mut cam = camera(&mut p, &comp);
+        set(&mut cam, "cameraOptions/dof", Value::Bool(true));
+        set(&mut cam, "cameraOptions/aperture", Value::Scalar(60.0));
+        set(&mut cam, "cameraOptions/focusDistance", Value::Scalar(bad));
+        let s = solid3(&mut p, &comp, [1.0, 1.0, 1.0], 60, 60, [100.0, 50.0, 0.0]);
+        push(&mut p, cid, cam);
+        push(&mut p, cid, s);
+        let cp = p.comp(cid).unwrap();
+        let ctx = crate::EvalCtx::new(&p, cid, cp, Tick::ZERO);
+        let cs = crate::three_d::camera::layer_camera(&ctx, &cp.layers[0]);
+        let f = cs.dof.unwrap().focus;
+        assert!((f - zoom()).abs() < 1e-9, "{bad}: evaluated to {f}, expected the fallback to zoom {}", zoom());
+        // The z = 0 plane is in focus: hard edge, finite pixels.
+        let img = render(&p, cid);
+        assert!(img.get(71, 50)[3] > 0.99 && img.get(69, 50)[3] < 0.01, "{bad}: the edge should be hard");
+        assert!(img.data.iter().all(|px| px.iter().all(|c| c.is_finite())), "{bad}: non-finite pixels");
+    }
+}
+
+/// The Classic 3D blur stays bounded for degenerate inputs: a 0%-scaled 3D layer off the focal
+/// plane (e.g. the first frame of a scale-in) or a huge but finite Focus Distance asks for a
+/// radius of billions of buffer pixels, whose padded buffer can't be allocated.
+#[test]
+fn dof_blur_radius_is_bounded_for_degenerate_inputs() {
+    let scene = |focus: f64, scale: f64| {
+        let (mut p, cid, comp) = setup();
+        let mut cam = camera(&mut p, &comp);
+        set(&mut cam, "cameraOptions/dof", Value::Bool(true));
+        set(&mut cam, "cameraOptions/aperture", Value::Scalar(60.0));
+        set(&mut cam, "cameraOptions/focusDistance", Value::Scalar(focus));
+        let mut s = solid3(&mut p, &comp, [1.0, 1.0, 1.0], 60, 60, [100.0, 50.0, 0.0]);
+        set(&mut s, "transform/scale", Value::Vec3([scale, scale, 100.0]));
+        push(&mut p, cid, cam);
+        push(&mut p, cid, s);
+        render(&p, cid)
+    };
+    let finite = |img: &effectcraft_raster::Image| img.data.iter().all(|px| px.iter().all(|c| c.is_finite()));
+    // A 0%-scaled layer 10 px off the focal plane: an ordinary defocus times 1/sx (sx = 1e-9).
+    assert!(finite(&scene(zoom() + 10.0, 0.0)), "zero-scaled: non-finite pixels");
+    // Huge but finite Focus Distances (typed in, or a large expression result): the blur is as
+    // large as the buffer budget allows, never refused (which would render the layer sharp).
+    // 1e307 overflows the circle of confusion itself to infinity: still the largest blur.
+    for focus in [1.0e12, 1.0e307] {
+        let img = scene(focus, 100.0);
+        assert!(finite(&img), "focus {focus:e}: non-finite pixels");
+        assert!(img.get(100, 50)[3] < 0.5, "focus {focus:e}: the layer should be spread out, not sharp ({})", img.get(100, 50)[3]);
+    }
+}
+
+/// The blur radius map of a plane: a 0%-scaled plane is degenerate on screen and isn't blurred;
+/// any other radius stays within the buffer budget's cap.
+#[test]
+fn dof_radii_skip_degenerate_planes_and_respect_the_cap() {
+    let radii = |focus: f64, scale: f64| {
+        let (mut p, cid, comp) = setup();
+        let mut cam = camera(&mut p, &comp);
+        set(&mut cam, "cameraOptions/dof", Value::Bool(true));
+        set(&mut cam, "cameraOptions/aperture", Value::Scalar(60.0));
+        set(&mut cam, "cameraOptions/focusDistance", Value::Scalar(focus));
+        let mut s = solid3(&mut p, &comp, [1.0, 1.0, 1.0], 60, 60, [100.0, 50.0, 0.0]);
+        set(&mut s, "transform/scale", Value::Vec3([scale, scale, 100.0]));
+        push(&mut p, cid, cam);
+        push(&mut p, cid, s);
+        let cp = p.comp(cid).unwrap();
+        let ctx = crate::EvalCtx::new(&p, cid, cp, Tick::ZERO);
+        let cs = super::camera::layer_camera(&ctx, &cp.layers[0]);
+        let dof = cs.dof.unwrap();
+        let cap = super::compose::dof_radius_cap(&dof, 60, 60);
+        (super::compose::dof_radii_at(&cs, &dof, ctx.world_matrix(&cp.layers[1]), (60, 60), [0.0; 2], 1.0, cap), cap)
+    };
+    let (r, _) = radii(zoom() + 10.0, 0.0);
+    assert!(r.iter().all(|&r| r == 0.0), "a 0%-scaled plane is not blurred");
+    let (r, cap) = radii(1.0e12, 100.0);
+    assert!(cap > 1000.0, "a 60×60 buffer may blur by well over 1000 px: {cap}");
+    assert!(r.iter().all(|&r| r as f64 <= cap && r as f64 > cap - 1.0), "huge focus: every radius at the cap {cap}");
+}
+
+/// Two layers that look the same on screen (400×100 at 100%, 1600×400 at 25%) at the same depth
+/// blur by the same amount on screen: the radius bound must not depend on the layer's scale.
+#[test]
+fn dof_blur_is_independent_of_layer_scale() {
+    let ramp = |w: u32, h: u32, scale: f64| {
+        let (mut p, cid, comp) = setup_sized(800, 400);
+        let zoom = 800.0 * 50.0 / 36.0;
+        let mut cam = camera(&mut p, &comp);
+        set(&mut cam, "cameraOptions/dof", Value::Bool(true));
+        set(&mut cam, "cameraOptions/aperture", Value::Scalar(200.0));
+        // coc = aperture·|z − f| / z: a 40 px comp radius on the z = 0 plane (depth = zoom).
+        set(&mut cam, "cameraOptions/focusDistance", Value::Scalar(zoom + 2.0 * 40.0 * zoom / 200.0));
+        let mut s = solid3(&mut p, &comp, [1.0, 1.0, 1.0], w, h, [400.0, 200.0, 0.0]);
+        set(&mut s, "transform/scale", Value::Vec3([scale, scale, 100.0]));
+        push(&mut p, cid, cam);
+        push(&mut p, cid, s);
+        let img = render(&p, cid);
+        soft_count(&img, (0..400).map(|x| (x, 200)))
+    };
+    let (full, quarter) = (ramp(400, 100, 100.0), ramp(1600, 400, 25.0));
+    assert!(full > 60, "the out-of-focus edge should be soft: {full}");
+    assert!(full.abs_diff(quarter) <= 2, "same on-screen layer, same depth: {full} px at 100% vs {quarter} px at 25%");
+}
+
+/// The same frame at Full and Half resolution shows the same blur (in comp pixels). The radius
+/// (~100 px) is large so that any bound that depends on the resolution would show.
+#[test]
+fn dof_blur_matches_across_render_resolutions() {
+    let (mut p, cid, comp) = setup_sized(800, 400);
+    let zoom = 800.0 * 50.0 / 36.0;
+    let mut cam = camera(&mut p, &comp);
+    set(&mut cam, "cameraOptions/dof", Value::Bool(true));
+    set(&mut cam, "cameraOptions/aperture", Value::Scalar(200.0));
+    set(&mut cam, "cameraOptions/focusDistance", Value::Scalar(2.0 * zoom));
+    let s = solid3(&mut p, &comp, [1.0, 1.0, 1.0], 400, 100, [400.0, 200.0, 0.0]);
+    push(&mut p, cid, cam);
+    push(&mut p, cid, s);
+    let ramp = |scale: f64| {
+        let img = render_frame(&p, cid, Tick::ZERO, scale);
+        let (w, h) = (img.width as i64, img.height as i64);
+        soft_count(&img, (0..w / 2).map(|x| (x, h / 2))) as f64 / scale
+    };
+    let (full, half) = (ramp(1.0), ramp(0.5));
+    assert!(full > 150.0, "a ~100 px radius must not be clamped: {full} comp px");
+    assert!((full - half).abs() <= 4.0, "Full {full} vs Half {half} comp px");
+}
+
+/// `Dof::coc` treats a non-finite focus or depth as in focus.
+#[test]
+fn dof_coc_is_zero_for_non_finite_inputs() {
+    let d = |focus: f64| super::camera::Dof { focus, aperture: 50.0, blur_level: 1.0, iris: Default::default(), highlight: Default::default() };
+    for bad in [f64::NAN, f64::INFINITY, f64::NEG_INFINITY] {
+        assert_eq!(d(bad).coc(500.0), 0.0, "focus {bad}");
+        assert_eq!(d(400.0).coc(bad), 0.0, "depth {bad}");
+    }
+    assert!(d(400.0).coc(500.0) > 0.0);
+}
+
+/// Pixels among `pts` whose alpha is strictly between 0.05 and 0.95.
+fn soft_count(img: &effectcraft_raster::Image, pts: impl Iterator<Item = (i64, i64)>) -> usize {
+    pts.filter(|&(x, y)| (0.05..0.95).contains(&img.get(x, y)[3])).count()
+}
+
 /// Pixels in column `x` whose alpha is strictly between 0.05 and 0.95.
 fn soft_px(img: &effectcraft_raster::Image, x: i64) -> usize {
-    (0..img.height as i64).filter(|&y| (0.05..0.95).contains(&img.get(x, y)[3])).count()
+    soft_count(img, (0..img.height as i64).map(|y| (x, y)))
 }
 
 #[test]

crates/script/src/matchnames.rs

@@ -90,6 +90,44 @@ pub fn stroke_dash(name: &str) -> Option<&'static str> {
 
 const TEXT_ANIMATOR: &[(&str, &str)] = &[("selectors", "ADBE Text Selectors"), ("properties", "ADBE Text Animator Properties")];
 
+/// Animator property ids and their stable After Effects scripting names. Shared by lookup,
+/// `.matchName`, and `addProperty` so the same property has one name in every direction.
+pub const TEXT_ANIMATOR_PROPERTIES: &[(&str, &str)] = &[
+    ("anchor", "ADBE Text Anchor Point 3D"),
+    ("position", "ADBE Text Position 3D"),
+    ("scale", "ADBE Text Scale 3D"),
+    ("skew", "ADBE Text Skew"),
+    ("rotation", "ADBE Text Rotation"),
+    ("opacity", "ADBE Text Opacity"),
+    ("fillColor", "ADBE Text Fill Color"),
+    ("fillHue", "ADBE Text Fill Hue"),
+    ("fillSaturation", "ADBE Text Fill Saturation"),
+    ("fillBrightness", "ADBE Text Fill Brightness"),
+    ("fillOpacity", "ADBE Text Fill Opacity"),
+    ("strokeColor", "ADBE Text Stroke Color"),
+    ("strokeHue", "ADBE Text Stroke Hue"),
+    ("strokeSaturation", "ADBE Text Stroke Saturation"),
+    ("strokeBrightness", "ADBE Text Stroke Brightness"),
+    ("strokeOpacity", "ADBE Text Stroke Opacity"),
+    ("strokeWidth", "ADBE Text Stroke Width"),
+    ("tracking", "ADBE Text Tracking Amount"),
+    ("lineAnchor", "ADBE Text Line Anchor"),
+    ("lineSpacing", "ADBE Text Line Spacing"),
+    ("characterOffset", "ADBE Text Character Offset"),
+    ("characterValue", "ADBE Text Character Replace"),
+    ("blur", "ADBE Text Blur"),
+];
+
+/// Companion properties that exist below an animator but are not kinds `addProperty` accepts:
+/// they come with Tracking (Track Type), Skew (Skew Axis) and per-character 3D Rotation
+/// (X and Y Rotation). Lookup and `.matchName` know them; `addProperty` does not.
+pub const TEXT_ANIMATOR_COMPANIONS: &[(&str, &str)] = &[
+    ("trackingType", "ADBE Text Track Type"),
+    ("skewAxis", "ADBE Text Skew Axis"),
+    ("rotationX", "ADBE Text Rotation X"),
+    ("rotationY", "ADBE Text Rotation Y"),
+];
+
 const TEXT_SELECTORS: &[(&str, &str)] =
     &[("rangeSelector", "ADBE Text Selector"), ("wigglySelector", "ADBE Text Wiggly Selector"), ("expressionSelector", "ADBE Text Expressible Selector")];
 
@@ -487,6 +525,9 @@ pub fn node(chain: &[&Node]) -> String {
         "text" if pid == "animators" => "ADBE Text Animator".into(),
         "text" if pid == "selectors" => find(TEXT_SELECTORS, id).map(str::to_string).unwrap_or_else(own),
         "text" if pid == "rangeSelector" => find(TEXT_RANGE_SELECTOR, id).map(str::to_string).unwrap_or_else(own),
+        "text" if pid == "properties" && chain.len() == 5 && chain.get(1).is_some_and(|n| n.match_id() == "animators") => {
+            find(TEXT_ANIMATOR_PROPERTIES, id).or_else(|| find(TEXT_ANIMATOR_COMPANIONS, id)).map(str::to_string).unwrap_or_else(own)
+        }
         "text" if grand.map(|g| g.match_id()) == Some("animators") => find(TEXT_ANIMATOR, id).map(str::to_string).unwrap_or_else(own),
         "cameraOptions" => find(CAMERA, id).map(str::to_string).unwrap_or_else(own),
         "lightOptions" => find(LIGHT, id).map(str::to_string).unwrap_or_else(own),
@@ -537,6 +578,30 @@ mod tests {
         assert_eq!(shape_kind("nope"), None);
     }
 
+    #[test]
+    fn text_animator_property_names_are_canonical_and_scoped() {
+        let n = |m: &str| Node::from(effectcraft_project::PropGroup::new(1, m, m));
+        let (text, animators, animator, properties) = (n("text"), n("animators"), n("animator"), n("properties"));
+        for (id, name) in TEXT_ANIMATOR_PROPERTIES {
+            let prop = n(id);
+            assert_eq!(node(&[&text, &animators, &animator, &properties, &prop]), *name);
+            assert_eq!(node(&[&properties, &prop]), *id, "an unrelated Properties group keeps its own ids");
+        }
+    }
+
+    /// #1063: the companions an animator property brings (Track Type, Skew Axis, X / Y Rotation)
+    /// have their After Effects names too, though `addProperty` does not accept them.
+    #[test]
+    fn text_animator_companions_have_after_effects_names() {
+        let n = |m: &str| Node::from(effectcraft_project::PropGroup::new(1, m, m));
+        let (text, animators, animator, properties) = (n("text"), n("animators"), n("animator"), n("properties"));
+        for (id, name) in TEXT_ANIMATOR_COMPANIONS {
+            let prop = n(id);
+            assert_eq!(node(&[&text, &animators, &animator, &properties, &prop]), *name);
+            assert!(!TEXT_ANIMATOR_PROPERTIES.iter().any(|(k, m)| k == id || m == name), "{id} is not an addProperty kind");
+        }
+    }
+
     #[test]
     fn text_range_selector_names() {
         let n = |m: &str| Node::from(effectcraft_project::PropGroup::new(1, m, m));

crates/script/src/model.rs

@@ -743,36 +743,12 @@ fn resolve_add(s: &Session, a: &J) -> R {
 /// A text animator property (`layer.addTextAnimatorProperty` key) from an After Effects match
 /// name or a display name.
 fn text_animator_property(name: &str) -> Option<&'static str> {
-    const AE: &[(&str, &str)] = &[
-        ("ADBE Text Anchor Point 3D", "anchor"),
-        ("ADBE Text Position 3D", "position"),
-        ("ADBE Text Scale 3D", "scale"),
-        ("ADBE Text Skew", "skew"),
-        ("ADBE Text Rotation", "rotation"),
-        ("ADBE Text Opacity", "opacity"),
-        ("ADBE Text Fill Color", "fillColor"),
-        ("ADBE Text Fill Hue", "fillHue"),
-        ("ADBE Text Fill Saturation", "fillSaturation"),
-        ("ADBE Text Fill Brightness", "fillBrightness"),
-        ("ADBE Text Fill Opacity", "fillOpacity"),
-        ("ADBE Text Stroke Color", "strokeColor"),
-        ("ADBE Text Stroke Hue", "strokeHue"),
-        ("ADBE Text Stroke Saturation", "strokeSaturation"),
-        ("ADBE Text Stroke Brightness", "strokeBrightness"),
-        ("ADBE Text Stroke Opacity", "strokeOpacity"),
-        ("ADBE Text Stroke Width", "strokeWidth"),
-        ("ADBE Text Tracking Amount", "tracking"),
-        ("ADBE Text Line Anchor", "lineAnchor"),
-        ("ADBE Text Line Spacing", "lineSpacing"),
-        ("ADBE Text Character Offset", "characterOffset"),
-        ("ADBE Text Character Replace", "characterValue"),
-        ("ADBE Text Blur", "blur"),
-    ];
-    if let Some((_, k)) = AE.iter().find(|(m, _)| m.eq_ignore_ascii_case(name)) {
+    let table = matchnames::TEXT_ANIMATOR_PROPERTIES;
+    if let Some((k, _)) = table.iter().find(|(_, m)| m.eq_ignore_ascii_case(name)) {
         return Some(k);
     }
     let n = loose(name);
-    AE.iter().map(|(_, k)| *k).find(|k| loose(k) == n || (n == "anchorpoint" && *k == "anchor") || (n == "trackingamount" && *k == "tracking"))
+    table.iter().map(|(k, _)| *k).find(|k| loose(k) == n || (n == "anchorpoint" && *k == "anchor") || (n == "trackingamount" && *k == "tracking"))
 }
 
 /// `app.findMenuCommandId(name)`: 1-based index of the command whose label matches (menu items

crates/script/src/prelude.js

@@ -734,9 +734,8 @@ PropertyGroup.prototype.addProperty = function (name) {
   } else if (r.kind === "animator") {
     uid = __call("layer.addTextAnimator", { comp: L.__comp, layer: L.__id, properties: [] }).animator;
   } else if (r.kind === "animatorProperty") {
-    var before = this.numProperties;
-    __call("layer.addTextAnimatorProperty", { comp: L.__comp, layer: L.__id, animator: r.animator, property: r.property });
-    return this.property(before + 1);
+    var added = __call("layer.addTextAnimatorProperty", { comp: L.__comp, layer: L.__id, animator: r.animator, property: r.property });
+    return this.property(added.index);
   } else if (r.kind === "selector") {
     var n0 = this.numProperties;
     __call("layer.addTextSelector", { comp: L.__comp, layer: L.__id, animator: r.animator, kind: r.selector });

crates/script/src/tests.rs

@@ -1719,6 +1719,50 @@ fn layer_property_resolves_transform_and_source_text_shortcuts() {
     assert_eq!(layer(c, "s").props.prop("transform/opacity").unwrap().value, KV::Scalar(25.0));
 }
 
+/// A text animator property added by its After Effects name is the one asked for, not its Tracking
+/// Type companion, and it can be found again by that name (#1063).
+#[test]
+fn scripted_text_animator_property_is_the_one_asked_for() {
+    let mut s = session();
+    let o = ok(
+        &mut s,
+        r#"
+        var c = app.project.items.addComp("Track", 960, 300, 1, 3, 30);
+        var t = c.layers.addText("MOVARA");
+        var a = t.property("ADBE Text Properties").property("ADBE Text Animators").addProperty("ADBE Text Animator");
+        var props = a.property("ADBE Text Animator Properties");
+        var added = props.addProperty("ADBE Text Tracking Amount");
+        added.setValue(20);
+        [added.name, props.property("ADBE Text Tracking Amount").value, props.property("ADBE Text Tracking Amount").name,
+         added.matchName, props.property(added.matchName).propertyIndex]
+        "#,
+    );
+    assert_eq!(o.result, json!(["Tracking Amount", 20, "Tracking Amount", "ADBE Text Tracking Amount", 2]));
+}
+
+/// The companion properties added with Tracking and Skew are found by their After Effects names,
+/// but cannot be added on their own (#1063).
+#[test]
+fn text_animator_companion_properties_resolve_by_name() {
+    let mut s = session();
+    let o = ok(
+        &mut s,
+        r#"
+        var c = app.project.items.addComp("Track", 960, 300, 1, 3, 30);
+        var t = c.layers.addText("MOVARA");
+        var props = t.property("ADBE Text Properties").property("ADBE Text Animators").addProperty("ADBE Text Animator").property("ADBE Text Animator Properties");
+        props.addProperty("ADBE Text Tracking Amount");
+        props.addProperty("ADBE Text Skew");
+        var type = props.property("ADBE Text Track Type");
+        var axis = props.property("ADBE Text Skew Axis");
+        var added = "";
+        try { props.addProperty("ADBE Text Track Type"); added = "added"; } catch (e) { added = "refused"; }
+        [type ? type.matchName : null, axis ? axis.matchName : null, added]
+        "#,
+    );
+    assert_eq!(o.result, json!(["ADBE Text Track Type", "ADBE Text Skew Axis", "refused"]));
+}
+
 /// #1936: an array whose length doesn't match the property's dimension is an error in After
 /// Effects, not a value to truncate or broadcast. Two values for a 3-D property stay legal.
 #[test]

crates/script/src/tests/ui_more.rs

@@ -222,7 +222,16 @@ fn position_now(s: &Session, layer: u64) -> [f64; 2] {
     let cid = s.active_comp_id().unwrap();
     let comp = s.project.comp(cid).unwrap();
     let l = comp.layer(effectcraft_engine::project::LayerId(layer)).unwrap();
-    let ctx = effectcraft_engine::render::EvalCtx { project: &s.project, comp_id: cid, comp, time: s.time(), expr: s.expr.as_deref(), footage: None };
+    let ctx = effectcraft_engine::render::EvalCtx {
+        project: &s.project,
+        comp_id: cid,
+        comp,
+        time: s.time(),
+        expr: s.expr.as_deref(),
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let v = ctx.value(l, l.props.prop("transform/position").unwrap()).components();
     [v[0], v[1]]
 }

crates/text/src/fonts.rs

@@ -707,14 +707,28 @@ const JAPANESE_FAMILIES: &[&str] = &[
 ];
 /// Han ideograph families for Simplified Chinese, in the order the platforms' own fallback tables
 /// prefer them (Windows, macOS, then the Linux/Noto names). Missing ones cost one name lookup each.
-const SIMPLIFIED_CHINESE_FAMILIES: &[&str] =
-    &["Microsoft YaHei", "SimSun", "PingFang SC", "Noto Sans CJK SC", "Noto Sans SC", "Source Han Sans SC", "WenQuanYi Micro Hei"];
+/// `Hiragino Sans GB`, `Heiti SC` and `Songti SC` are the Simplified faces a macOS install without
+/// the on-demand PingFang has (macOS 27 on an English install ships them, not PingFang): without
+/// them Chinese Han text fell through to the Japanese face and drew Japanese glyph forms (#453).
+const SIMPLIFIED_CHINESE_FAMILIES: &[&str] = &[
+    "Microsoft YaHei",
+    "SimSun",
+    "PingFang SC",
+    "Hiragino Sans GB",
+    "Heiti SC",
+    "Songti SC",
+    "STSong",
+    "Noto Sans CJK SC",
+    "Noto Sans SC",
+    "Source Han Sans SC",
+    "WenQuanYi Micro Hei",
+];
 /// The same for Traditional Chinese. The two scripts share almost all of their code points but not
 /// the glyph forms (`东` against `東`'s neighbours, `直`, `骨`), so one list for both drew a
 /// Traditional interface with Simplified forms - the faces do not differ in *coverage*, which is
 /// what the fallback search checks, so the script has to pick the list.
 const TRADITIONAL_CHINESE_FAMILIES: &[&str] =
-    &["Microsoft JhengHei", "MingLiU", "PingFang TC", "Heiti TC", "Hiragino Sans CNS", "Noto Sans CJK TC", "Noto Sans TC", "Source Han Sans TC"];
+    &["Microsoft JhengHei", "MingLiU", "PingFang TC", "Heiti TC", "Hiragino Sans CNS", "Songti TC", "Noto Sans CJK TC", "Noto Sans TC", "Source Han Sans TC"];
 const KOREAN_FAMILIES: &[&str] = &["Malgun Gothic", "Gulim", "Apple SD Gothic Neo", "Noto Sans CJK KR", "Noto Sans KR", "Source Han Sans KR", "NanumGothic"];
 /// The platforms' plain text families for the other scripts the bundled fonts lack, in the same
 /// order (Windows, macOS, then the Linux/Noto names).

crates/text/src/fonts/tests.rs

@@ -1,5 +1,14 @@
 use super::*;
 
+/// Run `test` again in a child process with `variable` set. The fixture faces below go into the
+/// process-global font database and its fallback caches, so only a process that runs one such test
+/// on its own can use them.
+#[cfg(not(target_arch = "wasm32"))]
+fn run_in_child(variable: &str, test: &str) {
+    let output = std::process::Command::new(std::env::current_exe().unwrap()).args(["--exact", test, "--nocapture"]).env(variable, "1").output().unwrap();
+    assert!(output.status.success(), "{}\n{}", String::from_utf8_lossy(&output.stdout), String::from_utf8_lossy(&output.stderr));
+}
+
 /// Concurrent language requests must neither choose another context's font nor reuse its
 /// cached family order. Synthetic fonts in a child process keep this independent of the host
 /// font installation and of other tests that exercise the process-global database/locale.
@@ -8,12 +17,7 @@ use super::*;
 fn cjk_requests_keep_their_language_and_cache_entries() {
     const CHILD: &str = "EFFECTCRAFT_TEST_ISOLATED_CJK";
     if std::env::var_os(CHILD).is_none() {
-        let output = std::process::Command::new(std::env::current_exe().unwrap())
-            .args(["--exact", "fonts::tests::cjk_requests_keep_their_language_and_cache_entries", "--nocapture"])
-            .env(CHILD, "1")
-            .output()
-            .unwrap();
-        assert!(output.status.success(), "{}\n{}", String::from_utf8_lossy(&output.stdout), String::from_utf8_lossy(&output.stderr));
+        run_in_child(CHILD, "fonts::tests::cjk_requests_keep_their_language_and_cache_entries");
         return;
     }
     let families = [("ja", "Yu Gothic"), ("zh-hans", "Microsoft YaHei"), ("zh-hant", "Microsoft JhengHei"), ("ko", "Malgun Gothic")];
@@ -71,6 +75,52 @@ fn cjk_requests_keep_their_language_and_cache_entries() {
     }
 }
 
+/// #453: with a Chinese interface, a Han ideograph that both a Chinese and a Japanese face cover
+/// must reach the installed Simplified Chinese family first, or Chinese text in a composition is
+/// drawn with Japanese glyph forms. Fixture faces named after the macOS families keep this
+/// independent of the host's fonts and of rendering. Before the fix the Simplified list named none
+/// of the macOS faces a stock install has, so the walk below reached the Japanese face - the
+/// regression this guards.
+#[test]
+#[cfg(not(target_arch = "wasm32"))]
+fn zh_hans_han_fallback_puts_the_chinese_family_first() {
+    const CHILD: &str = "EFFECTCRAFT_TEST_ZH_HANS_ORDER";
+    if std::env::var_os(CHILD).is_none() {
+        run_in_child(CHILD, "fonts::tests::zh_hans_han_fallback_puts_the_chinese_family_first");
+        return;
+    }
+    let mut ids = Vec::new();
+    {
+        let mut d = db().write().unwrap();
+        d.scanned = true; // This test process uses only bundled and synthetic fonts.
+        // The Japanese face is added first, so scan order cannot be what picks the Chinese one.
+        for family in ["Hiragino Sans", "Hiragino Sans GB"] {
+            let mut data = test_font(family);
+            let table = data[12..12 + 8 * 16].as_chunks::<16>().0.iter().find(|t| &t[..4] == b"cmap").unwrap();
+            let cmap = u32::from_be_bytes(table[8..12].try_into().unwrap()) as usize + 12;
+            // Map 页 to the fixture's triangle glyph instead of its private-use range.
+            for (offset, value) in [(16, '页' as u16), (24, '页' as u16), (30, 2u16.wrapping_sub('页' as u16))] {
+                data[cmap + offset..cmap + offset + 2].copy_from_slice(&value.to_be_bytes());
+            }
+            let data = Arc::new(data);
+            let names = read_faces_bytes(&data).into_iter().next().unwrap();
+            ids.push(push(&mut d, info_from(names, FaceData::Shared(data), "test")));
+        }
+    }
+    let &[japanese, chinese] = ids.as_slice() else { panic!("two fixture faces expected: {ids:?}") };
+    let base = resolve("Inter", "Regular").face;
+    assert!(face(japanese).has_char('页') && face(chinese).has_char('页'));
+    // The fallback list itself, before any coverage check: the Chinese family comes first for
+    // zh-hans and second for ja, whether or not either face can draw the probe.
+    let zh_hans: Vec<FaceId> = family_faces(FallbackScript::Han, &face(base), CjkLocale::Simplified).to_vec();
+    assert_eq!(zh_hans, [chinese, japanese], "zh-hans tries the Chinese family first");
+    let ja: Vec<FaceId> = family_faces(FallbackScript::Han, &face(base), CjkLocale::Japanese).to_vec();
+    assert_eq!(ja, [japanese, chinese], "ja keeps the Japanese family first");
+    // ...and the face a layout actually gets for the shared ideograph.
+    assert_eq!(face(fallback_for_locale('页', base, "zh-hans")).info.family, "Hiragino Sans GB");
+    assert_eq!(face(fallback_for_locale('页', base, "ja")).info.family, "Hiragino Sans");
+}
+
 #[test]
 fn extra_font_dirs_come_from_a_path_list() {
     assert!(extra_dirs(None).is_empty());
@@ -93,24 +143,47 @@ fn bundled_families_and_resolution() {
     assert!(!b.synth_bold);
     let faces = all_faces();
     assert!(faces.iter().any(|f| f.info.family == "Noto Serif" && f.info.style == "Regular" && f.info.origin == "bundled"));
-    // A real installed Bold Italic takes priority. Partial installed families can instead
-    // supply the nearest weight/slant, so neither synthesis flag is fixed by the OS.
+    // A real installed Bold Italic — the face's own style, or a named instance of a variable
+    // face — takes priority. Partial installed families can instead supply the nearest
+    // weight/slant, so neither synthesis flag is fixed by the OS.
     for family in ["Noto Serif", "Inter"] {
         let resolved = resolve(family, "Bold Italic");
         let selected = face(resolved.face);
         assert!(selected.info.family.eq_ignore_ascii_case(family));
         assert!(!resolved.missing);
         let candidates: Vec<_> = faces.iter().filter(|f| f.info.family.eq_ignore_ascii_case(family)).collect();
-        if let Some(exact) = candidates.iter().find(|f| f.info.style.eq_ignore_ascii_case("Bold Italic")) {
+        let exact = candidates
+            .iter()
+            .find(|f| f.info.style.eq_ignore_ascii_case("Bold Italic"))
+            .or_else(|| candidates.iter().find(|f| f.info.instances.iter().any(|i| i.style.eq_ignore_ascii_case("Bold Italic"))));
+        if let Some(exact) = exact {
             assert_eq!(resolved.face, exact.id, "real style wins for {family}");
+            let expected_instance = if exact.info.style.eq_ignore_ascii_case("Bold Italic") {
+                None
+            } else {
+                exact.info.instances.iter().position(|i| i.style.eq_ignore_ascii_case("Bold Italic")).and_then(|i| u16::try_from(i).ok())
+            };
+            assert_eq!(resolved.instance, expected_instance, "exact style instance for {family}");
             assert!(!resolved.synth_bold && !resolved.synth_italic);
         } else {
-            // Italic mismatch dominates any supported font weight distance.
-            let distance = |f: &Face| u32::from(f.info.weight.abs_diff(700)) + if f.info.italic { 0 } else { 1_000 };
-            let nearest = candidates.iter().map(|f| distance(f)).min().unwrap();
-            assert_eq!(distance(&selected), nearest, "closest available style for {family}");
-            assert_eq!(resolved.synth_bold, selected.info.weight <= 500);
-            assert_eq!(resolved.synth_italic, !selected.info.italic);
+            // Italic mismatch dominates any supported font weight distance. Named instances
+            // resolve at their effective weight and slant, not the face's defaults.
+            let selected_instance = resolved.instance.and_then(|i| selected.info.instances.get(usize::from(i)));
+            let selected_weight = selected_instance.map_or(selected.info.weight, |i| i.weight(selected.info.weight));
+            let selected_italic = selected_instance.map_or(selected.info.italic, |i| i.italic(selected.info.italic));
+            let distance = |weight: u16, italic: bool| u32::from(weight.abs_diff(700)) + if italic { 0 } else { 1_000 };
+            let nearest = candidates
+                .iter()
+                .flat_map(|f| {
+                    std::iter::once((f.info.weight, f.info.italic))
+                        .chain(f.info.instances.iter().map(move |i| (i.weight(f.info.weight), i.italic(f.info.italic))))
+                })
+                .map(|(weight, italic)| distance(weight, italic))
+                .min()
+                .unwrap();
+            assert_eq!(distance(selected_weight, selected_italic), nearest, "closest available style for {family}");
+            assert_eq!(resolved.synth_bold, selected_weight <= 500);
+            assert_eq!(resolved.synth_italic, !selected_italic);
         }
     }
 }
@@ -164,6 +237,7 @@ fn variable_named_instances_resolve_and_list() {
         ("Regular", 400.0, Some("EffectCraftInstanceTest-Regular")),
         ("Black", 900.0, Some("EffectCraftInstanceTest-Black")),
         ("Extra Bold", 800.0, None),
+        ("Bold Italic", 700.0, Some("EffectCraftInstanceTest-BoldItalic")),
     ];
     assert_eq!(add_font_data(crate::sfnt::test_font::variable(FAMILY, &instances, true)).len(), 1);
     let wght = |r: &Resolved| instance_variations(r);
@@ -185,10 +259,15 @@ fn variable_named_instances_resolve_and_list() {
     assert_eq!(wght(&ps), vec![("wght".to_string(), 900.0)]);
     assert_eq!(wght(&resolve("EffectCraftInstanceTest-ExtraBold", "")), vec![("wght".to_string(), 800.0)]);
     assert_eq!(wght(&resolve("effectcraft instance test extra bold", "")), vec![("wght".to_string(), 800.0)]);
+    // A named instance keeps its own index, so layout applies its axis values.
+    let bold_italic = resolve(FAMILY, "Bold Italic");
+    assert!(!bold_italic.missing && !bold_italic.synth_bold && !bold_italic.synth_italic);
+    assert_eq!((bold_italic.face, bold_italic.instance), (black.face, Some(4)));
+    assert_eq!(wght(&bold_italic), vec![("wght".to_string(), 700.0)]);
     // The font menu lists every instance, in weight order.
     let fams = families();
     let styles = &fams.iter().find(|(f, _)| f == FAMILY).unwrap().1;
-    assert_eq!(styles, &["Light", "Regular", "Extra Bold", "Black"]);
+    assert_eq!(styles, &["Light", "Regular", "Extra Bold", "Black", "Bold Italic"]);
     // Static fonts are untouched.
     assert_eq!(resolve("Inter", "Bold").instance, None);
 }

crates/ui-egui/src/header.rs

@@ -94,9 +94,11 @@ fn tool_slot(app: &mut EffectcraftApp, ui: &mut egui::Ui, p: &egui::Painter, si:
         ));
     }
     app.auto.add_response(&format!("tools.{cur:?}"), &resp, cur.label());
+    // The drawn tooltip asks the catalog; the automation label above keeps the English name.
+    let label = crate::i18n::tr(cur.label());
     let tip = match cur.shortcut() {
-        Some(s) => format!("{} ({})", cur.label(), crate::menus::shortcut_text(s)),
-        None => cur.label().to_string(),
+        Some(s) => format!("{} ({})", label, crate::menus::shortcut_text(s)),
+        None => label.to_string(),
     };
     let resp = resp.on_hover_text(tip);
     let held = ui.data(|d| d.get_temp::<egui::Id>(held_id)) == Some(id);
@@ -145,7 +147,7 @@ fn slot_flyout(app: &mut EffectcraftApp, ui: &mut egui::Ui, si: usize, slot: &[T
     let close_behavior = if held && resp.clicked() { egui::PopupCloseBehavior::IgnoreClicks } else { egui::PopupCloseBehavior::CloseOnClickOutside };
     egui::Popup::menu(resp).style(crate::widgets::menu_style).open_memory(command).close_behavior(close_behavior).show(|ui| {
         for tool in slot.iter() {
-            let row = ui.selectable_label(app.ui.tool == *tool, tool.label());
+            let row = ui.selectable_label(app.ui.tool == *tool, crate::i18n::tr(tool.label()));
             app.auto.add(&format!("tools.select.{tool:?}"), row.rect, tool.label());
             if row.clicked() {
                 app.ui.tool = *tool;

crates/ui-egui/src/i18n/effects.rs

@@ -143,6 +143,7 @@ const SIMPLIFIED_CHINESE: &[Row] = &[
     ("ec.3d.fog3d", "Fog 3D", "雾 3D"),
     ("ec.3d.identifier", "IDentifier", "IDentifier"),
     ("ec.3d.idmatte", "ID Matte", "ID 遮罩"),
+    ("ec.3d.instance3d", "3D Layer Instance", "3D 图层实例"),
     ("ec.audio.backwards", "Backwards", "倒放"),
     ("ec.audio.basstreble", "Bass & Treble", "低音和高音"),
     ("ec.audio.compressor", "Compressor", "压缩程序"),
@@ -802,6 +803,7 @@ const GEORGIAN: &[Row] = &[
     ("ec.3d.fog3d", "Fog 3D", "3D ნისლი"),
     ("ec.3d.identifier", "IDentifier", "IDentifier"),
     ("ec.3d.idmatte", "ID Matte", "ID მატი"),
+    ("ec.3d.instance3d", "3D Layer Instance", "3D Layer Instance"),
     ("ec.audio.backwards", "Backwards", "უკუღმა"),
     ("ec.audio.basstreble", "Bass & Treble", "ბასი და ტრებლი"),
     ("ec.audio.compressor", "Compressor", "კომპრესორი"),

crates/ui-egui/src/i18n/ui.rs

@@ -1643,6 +1643,49 @@ const SIMPLIFIED_CHINESE: &[(&str, &str)] = &[
     ("Total Offset", "总偏移"),
     ("Per Layer", "每个图层"),
     ("Track", "跟踪"),
+    ("Selection Tool", "选择工具"),
+    ("Hand Tool", "抓手工具"),
+    ("Zoom Tool", "缩放工具"),
+    ("Orbit Around Cursor Tool", "绕行摄像机工具"),
+    ("Pan Under Cursor Tool", "平移摄像机工具"),
+    ("Dolly Towards Cursor Tool", "推拉摄像机工具"),
+    ("Rotation Tool", "旋转工具"),
+    ("Pan Behind (Anchor Point) Tool", "向后平移工具"),
+    ("Rectangle Tool", "矩形工具"),
+    ("Rounded Rectangle Tool", "圆角矩形工具"),
+    ("Ellipse Tool", "椭圆工具"),
+    ("Polygon Tool", "多边形工具"),
+    ("Star Tool", "星形工具"),
+    ("Pen Tool", "钢笔工具"),
+    ("Add Vertex Tool", "添加顶点工具"),
+    ("Delete Vertex Tool", "删除顶点工具"),
+    ("Convert Vertex Tool", "转换顶点工具"),
+    ("Mask Feather Tool", "蒙版羽化工具"),
+    ("Horizontal Type Tool", "横排文字工具"),
+    ("Vertical Type Tool", "直排文字工具"),
+    ("Brush Tool", "画笔工具"),
+    ("Clone Stamp Tool", "仿制图章工具"),
+    ("Eraser Tool", "橡皮擦工具"),
+    ("Roto Brush Tool", "Roto 笔刷工具"),
+    ("Refine Edge Tool", "调整边缘工具"),
+    ("Object Matte Tool", "对象遮罩工具"),
+    ("Puppet Position Pin Tool", "人偶位置控点工具"),
+    ("Puppet Starch Pin Tool", "人偶扑粉控点工具"),
+    ("Puppet Bend Pin Tool", "人偶弯曲控点工具"),
+    ("Puppet Advanced Pin Tool", "人偶高级控点工具"),
+    ("Puppet Overlap Pin Tool", "人偶重叠控点工具"),
+    ("Shortcut", "快捷键"),
+    ("Range", "范围"),
+    ("Play From", "从以下位置播放"),
+    ("Frame Rate", "帧速率"),
+    ("Resolution", "分辨率"),
+    ("Overlays", "叠加"),
+    ("Layer Controls", "图层控制"),
+    ("Loop", "循环"),
+    ("Cache Before Playback", "播放前缓存"),
+    ("Pre-roll", "预卷"),
+    ("Post-roll", "后卷"),
+    ("If caching, play cached frames", "缓存时播放已缓存帧"),
 ];
 
 const TRADITIONAL_CHINESE: &[(&str, &str)] = &[
@@ -2330,6 +2373,49 @@ const TRADITIONAL_CHINESE: &[(&str, &str)] = &[
     ("Total Offset", "總偏移"),
     ("Per Layer", "每個圖層"),
     ("Track", "追蹤"),
+    ("Selection Tool", "選取工具"),
+    ("Hand Tool", "手形工具"),
+    ("Zoom Tool", "縮放工具"),
+    ("Orbit Around Cursor Tool", "繞行攝影機工具"),
+    ("Pan Under Cursor Tool", "平移攝影機工具"),
+    ("Dolly Towards Cursor Tool", "推拉攝影機工具"),
+    ("Rotation Tool", "旋轉工具"),
+    ("Pan Behind (Anchor Point) Tool", "向後平移工具"),
+    ("Rectangle Tool", "矩形工具"),
+    ("Rounded Rectangle Tool", "圓角矩形工具"),
+    ("Ellipse Tool", "橢圓工具"),
+    ("Polygon Tool", "多邊形工具"),
+    ("Star Tool", "星形工具"),
+    ("Pen Tool", "筆型工具"),
+    ("Add Vertex Tool", "添加頂點工具"),
+    ("Delete Vertex Tool", "刪除頂點工具"),
+    ("Convert Vertex Tool", "轉換頂點工具"),
+    ("Mask Feather Tool", "遮色片羽化工具"),
+    ("Horizontal Type Tool", "橫排文字工具"),
+    ("Vertical Type Tool", "垂直文字工具"),
+    ("Brush Tool", "筆刷工具"),
+    ("Clone Stamp Tool", "仿製圖章工具"),
+    ("Eraser Tool", "橡皮擦工具"),
+    ("Roto Brush Tool", "Roto 筆刷工具"),
+    ("Refine Edge Tool", "調整邊緣工具"),
+    ("Object Matte Tool", "物件遮色片工具"),
+    ("Puppet Position Pin Tool", "人偶位置控點工具"),
+    ("Puppet Starch Pin Tool", "人偶撲粉控點工具"),
+    ("Puppet Bend Pin Tool", "人偶彎曲控點工具"),
+    ("Puppet Advanced Pin Tool", "人偶高級控點工具"),
+    ("Puppet Overlap Pin Tool", "人偶重疊控點工具"),
+    ("Shortcut", "快速鍵"),
+    ("Range", "範圍"),
+    ("Play From", "從下列位置播放"),
+    ("Frame Rate", "影格速率"),
+    ("Resolution", "解析度"),
+    ("Overlays", "覆疊"),
+    ("Layer Controls", "圖層控制"),
+    ("Loop", "循環"),
+    ("Cache Before Playback", "播放前快取"),
+    ("Pre-roll", "預卷"),
+    ("Post-roll", "後卷"),
+    ("If caching, play cached frames", "快取時播放已快取影格"),
 ];
 
 /// Ukrainian (uk): original translations of the same interface rows as the Chinese catalogs.
@@ -5745,6 +5831,7 @@ mod tests {
         ("menus/frontend.rs", include_str!("../menus/frontend.rs")),
         ("menus/invoke.rs", include_str!("../menus/invoke.rs")),
         ("menus/shortcuts.rs", include_str!("../menus/shortcuts.rs")),
+        ("state.rs", include_str!("../state.rs")),
         ("prefs_live.rs", include_str!("../prefs_live.rs")),
         ("widgets.rs", include_str!("../widgets.rs")),
         ("panels/anim_tools.rs", include_str!("../panels/anim_tools.rs")),
@@ -5822,6 +5909,55 @@ mod tests {
         rows.iter().find(|(source, _)| *source == en).map_or(en, |(_, translated)| *translated)
     }
 
+    #[test]
+    fn the_toolbar_asks_the_catalog_for_the_tool_names() {
+        let header = include_str!("../header.rs");
+        for call in ["crate::i18n::tr(tool.label())", "crate::i18n::tr(cur.label())"] {
+            assert!(header.contains(call), "header.rs no longer draws {call}");
+        }
+        assert!(
+            header.contains("app.auto.add(&format!(\"tools.select.{tool:?}\"), row.rect, tool.label())"),
+            "the automation label must stay the English tool name"
+        );
+    }
+
+    #[test]
+    fn the_preview_panel_labels_are_translated() {
+        // The Preview panel draws these from a local closure, a check table and a roll tuple, none of
+        // which the call-shape scan sees; they had no rows at all.
+        for key in [
+            "Shortcut",
+            "Range",
+            "Play From",
+            "Frame Rate",
+            "Resolution",
+            "Overlays",
+            "Layer Controls",
+            "Loop",
+            "Cache Before Playback",
+            "Pre-roll",
+            "Post-roll",
+            "If caching, play cached frames",
+        ] {
+            for (name, table) in [("Simplified", SIMPLIFIED_CHINESE), ("Traditional", TRADITIONAL_CHINESE)] {
+                let value = table.iter().find(|(k, _)| *k == key).map(|(_, v)| *v);
+                assert!(value.is_some_and(|v| !v.is_empty()), "{key} has no {name} row");
+            }
+        }
+        // A row is not a translation until the panel asks for it: the labels drawn one by one carry
+        // `tr(..)`, and the table and the roll tuple wrap the text they read at the call.
+        let source = include_str!("../panels/misc.rs");
+        for literal in ["Shortcut", "Range", "Play From", "Frame Rate", "Resolution", "Full Screen", "If caching, play cached frames"] {
+            assert!(source.contains(&format!("tr(\"{literal}\")")), "{literal} is drawn without asking the catalog");
+        }
+        for call in ["check_row(app, ui, &p, pos2(cx, cy), key, tr(text), on)", "Align2::LEFT_CENTER, tr(text),"] {
+            assert!(source.contains(call), "{call} no longer asks the catalog");
+        }
+        for table in ["\"Overlays\"", "\"Layer Controls\"", "\"Loop\"", "\"Cache Before Playback\"", "\"Pre-roll\"", "\"Post-roll\""] {
+            assert!(source.contains(table), "{table} is not in the panel");
+        }
+    }
+
     /// A row that translates nothing, repeats a source string, or changes the number of values the
     /// English source carries is a bug in the catalog itself.
     #[test]

crates/ui-egui/src/menus/entries.rs

@@ -119,7 +119,8 @@ pub(crate) fn entry_enabled(app: &EffectcraftApp, e: &MenuEntry) -> bool {
         }
     }
     if e.command == "edit.clear" && app.ui.focused == PanelKind::Project {
-        return app.session.is_enabled("project.delete");
+        // An open text edit stands down: Clear must not delete the comp being typed into (#2227).
+        return app.session.state.text_edit.is_none() && app.session.is_enabled("project.delete");
     }
     if e.command == "edit.clear" && app.ui.focused == PanelKind::RenderQueue {
         return !app.session.is_rendering() && !app.session.project.render_queue.is_empty();

crates/ui-egui/src/menus/invoke.rs

@@ -151,7 +151,16 @@ fn vertex_delta(app: &EffectcraftApp, layer: effectcraft_engine::project::LayerI
     let s = &app.session;
     let (Some(cid), Some(comp)) = (s.active_comp_id(), s.active_comp()) else { return d };
     let Some(l) = comp.layer(layer) else { return d };
-    let ectx = effectcraft_engine::render::EvalCtx { project: &s.project, comp_id: cid, comp, time: s.time(), expr: s.expr.as_deref(), footage: None };
+    let ectx = effectcraft_engine::render::EvalCtx {
+        project: &s.project,
+        comp_id: cid,
+        comp,
+        time: s.time(),
+        expr: s.expr.as_deref(),
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let (l2c, _) = crate::panels::viewer::l2c(&ectx, l);
     l2c.inverse().map_or(d, |inv| {
         let v = inv.apply_vec(vec2(d[0], d[1]));
@@ -223,8 +232,13 @@ pub fn invoke(app: &mut EffectcraftApp, ctx: &egui::Context, id: &str, params: V
             return run_engine(app, ctx, "edit.pasteSvg", json!({"svg": svg}));
         }
     }
-    // Clear follows panel focus, including the Edit menu and keyboard shortcut.
+    // Clear follows panel focus, including the Edit menu and keyboard shortcut. An open text
+    // edit stands down: the user is working in a composition, and the Project-panel redirect
+    // would delete it without asking when nothing uses it (#2227).
     if id == "edit.clear" && params.as_object().is_some_and(|p| p.is_empty()) && app.ui.focused == PanelKind::Project {
+        if app.session.state.text_edit.is_some() {
+            return Ok(Value::Null);
+        }
         // Through `invoke`, so deleting items that compositions use still asks first (M3.16).
         return invoke(app, ctx, "project.delete", json!({}));
     }

crates/ui-egui/src/panels/effect_controls/panel.rs

@@ -166,7 +166,16 @@ pub fn show(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
     let comp_name = app.session.project.item(cid).map(|i| i.name.clone()).unwrap_or_default();
     let snap_project = app.session.project.clone();
     let snap_expr = app.session.expr.clone();
-    let ectx = EvalCtx { project: &snap_project, comp_id: cid, comp: &comp, time: app.session.time(), expr: snap_expr.as_deref(), footage: None };
+    let ectx = EvalCtx {
+        project: &snap_project,
+        comp_id: cid,
+        comp: &comp,
+        time: app.session.time(),
+        expr: snap_expr.as_deref(),
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let hdr = Rect::from_min_size(rect.min, vec2(rect.width(), 24.0));
     p.text(pos2(hdr.min.x + 10.0, hdr.center().y), Align2::LEFT_CENTER, format!("{} • {}", comp_name, layer.name), Tokens::ui(11.5), t.text_dim);
     p.line_segment([hdr.left_bottom(), hdr.right_bottom()], Stroke::new(1.0, t.separator));

crates/ui-egui/src/panels/expr_editor.rs

@@ -111,6 +111,7 @@ pub const COMPLETIONS: &[&str] = &[
     "ease",
     "easeIn",
     "easeOut",
+    "bezier",
     "clamp",
     "random",
     "gaussRandom",

crates/ui-egui/src/panels/layer_panel.rs

@@ -104,7 +104,16 @@ fn render_tex(
     match cached {
         Some(c) if c.key == key => Some(c),
         _ => {
-            let ectx = EvalCtx { project: &app.session.project, comp_id: cid, comp, time, expr: app.session.expr.as_deref(), footage: None };
+            let ectx = EvalCtx {
+                project: &app.session.project,
+                comp_id: cid,
+                comp,
+                time,
+                expr: app.session.expr.as_deref(),
+                footage: None,
+                property_overrides: &[],
+                media_overrides: &[],
+            };
             let mut r = Renderer::new(&app.session.project, &*app.session.footage, RenderOpts { scale, ..Default::default() });
             r.expr = app.session.expr.as_deref();
             r.cache = Some(&app.session.layer_cache);

crates/ui-egui/src/panels/misc.rs

@@ -61,7 +61,7 @@ pub fn preview(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
     let mut yy = y + 46.0;
 
     // Shortcut.
-    label(yy, "Shortcut");
+    label(yy, tr("Shortcut"));
     let names: Vec<String> = PreviewShortcut::ALL.iter().map(|s| s.label().to_string()).collect();
     if let Some(i) = dropdown_row(
         app,
@@ -91,14 +91,14 @@ pub fn preview(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
         let row = if i < 4 { i / 2 } else { i - 2 };
         let cx = x0 + col as f32 * 110.0 - 2.0;
         let cy = yy + row as f32 * 22.0;
-        if check_row(app, ui, &p, pos2(cx, cy), key, text, on) {
+        if check_row(app, ui, &p, pos2(cx, cy), key, tr(text), on) {
             changes.push(json!({"shortcut": current.id(), key: !on}));
         }
     }
     yy += 4.0 * 22.0 + 6.0;
 
     // Range (and the pre/post-roll of Play Around Current Time).
-    label(yy, "Range");
+    label(yy, tr("Range"));
     let ranges: Vec<String> = PreviewRange::ALL.iter().map(|r| r.label().to_string()).collect();
     let range_ids = ["workArea", "workAreaExtended", "entireDuration", "aroundCurrentTime"];
     if let Some(i) = dropdown_row(
@@ -116,7 +116,7 @@ pub fn preview(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
     if o.range == PreviewRange::AroundCurrentTime {
         for (k, (key, text, v)) in [("preRoll", "Pre-roll", o.pre_roll), ("postRoll", "Post-roll", o.post_roll)].into_iter().enumerate() {
             let lx = xv + k as f32 * 100.0;
-            p.text(pos2(lx, yy), Align2::LEFT_CENTER, text, Tokens::ui(11.5), t.text_dim);
+            p.text(pos2(lx, yy), Align2::LEFT_CENTER, tr(text), Tokens::ui(11.5), t.text_dim);
             let (r, nv, _) = widgets::hot_number_at(
                 ui,
                 pos2(lx + 52.0, yy - 9.0),
@@ -134,7 +134,7 @@ pub fn preview(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
     }
 
     // Play From.
-    label(yy, "Play From");
+    label(yy, tr("Play From"));
     let froms: Vec<String> = PlayFrom::ALL.iter().map(|f| f.label().to_string()).collect();
     if let Some(i) = dropdown_row(
         app,
@@ -151,7 +151,7 @@ pub fn preview(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
 
     // Frame Rate, Skip, Resolution.
     let comp_fps = app.session.active_comp().map(|c| c.frame_rate.as_f64());
-    label(yy, "Frame Rate");
+    label(yy, tr("Frame Rate"));
     const RATES: [f64; 12] = [8.0, 10.0, 12.0, 12.5, 15.0, 23.976, 24.0, 25.0, 29.97, 30.0, 50.0, 60.0];
     let auto = format!("({:.2}) Auto", comp_fps.unwrap_or(0.0));
     let mut rates = vec![auto.clone()];
@@ -180,7 +180,7 @@ pub fn preview(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
         changes.push(json!({"shortcut": current.id(), "skip": nv.round() as u32}));
     }
     yy += 24.0;
-    label(yy, "Resolution");
+    label(yy, tr("Resolution"));
     let ress: Vec<String> = PreviewResolution::ALL.iter().map(|r| r.label().to_string()).collect();
     let res_ids = ["auto", "full", "half", "third", "quarter", "custom"];
     if let Some(i) = dropdown_row(
@@ -209,7 +209,7 @@ pub fn preview(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
         }
     }
     yy += 24.0;
-    if check_row(app, ui, &p, pos2(x0 - 2.0, yy), "fullScreen", "Full Screen", o.full_screen) {
+    if check_row(app, ui, &p, pos2(x0 - 2.0, yy), "fullScreen", tr("Full Screen"), o.full_screen) {
         changes.push(json!({"shortcut": current.id(), "fullScreen": !o.full_screen}));
     }
     yy += 24.0;
@@ -217,7 +217,7 @@ pub fn preview(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
     // What stopping does.
     p.text(pos2(x0, yy), Align2::LEFT_CENTER, tr_args("On ({}) stop:", &[&(current.label())]), Tokens::ui(11.5), t.text_dim);
     yy += 20.0;
-    if check_row(app, ui, &p, pos2(x0 - 2.0, yy), "playCachedFrames", "If caching, play cached frames", o.play_cached_frames) {
+    if check_row(app, ui, &p, pos2(x0 - 2.0, yy), "playCachedFrames", tr("If caching, play cached frames"), o.play_cached_frames) {
         changes.push(json!({"shortcut": current.id(), "playCachedFrames": !o.play_cached_frames}));
     }
     yy += 22.0;

crates/ui-egui/src/panels/properties.rs

@@ -70,7 +70,16 @@ pub fn show(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
     let project = app.session.project.clone();
     let expr = app.session.expr.clone();
     let now = app.session.time();
-    let ectx = EvalCtx { project: &project, comp_id: cid, comp: &comp, time: now, expr: expr.as_deref(), footage: None };
+    let ectx = EvalCtx {
+        project: &project,
+        comp_id: cid,
+        comp: &comp,
+        time: now,
+        expr: expr.as_deref(),
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let x0 = rect.min.x + PAD;
     let w = rect.width() - 2.0 * PAD;
     let scroll = widgets::PanelScroll::begin(ui, egui::Id::unique("props-scroll"), rect);