In a segment that is Bezier on one side and linear on the other, the linear
side keeps the segment's average speed, but with the 16.67 % influence After
Effects shows for linear keys in the Keyframe Velocity dialog (and reports to
scripts), not 33.3 %. Measured on an After Effects 2026 time-remap render (a
square at x = 50 + 455 * remap): out of a key at 2 s (3.5, speed 0, influence
50 %) into a linear key at 4 s (0.5), AE plays 3.290 at 2.5 s and 2.657 at
3 s; EffectCraft played 3.308 and 2.629 (8 and 13 px off), now the same
square positions to the pixel.
LINEAR_SIDE_INFLUENCE is used by evaluation (scalar, per-dimension, paths and
spatial), side_ease (Graph Editor, velocity dialog, keyIn/OutTemporalEase) and
the Lottie export, so exported easing plays as EffectCraft does. Segments
linear on both sides stay straight lines.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Problem: Object Matte had no After Effects comparison, and none can be made
on this Linux machine (no After Effects). The gap notes still listed the
viewer tool, background job and disk cache as missing.
Fix: docs/fidelity/object-matte.md states plainly that nothing is measured
yet and pins down the comparison for when an After Effects 26.2+ reference
is available: four original or openly licensed clips (the synthetic moving
disk from the engine tests, the disk with a jump, two objects with a box
prompt, one CC0/CC BY real clip), the prompt and settings, where reference
mattes stay (gitignored), and the metrics: per-frame IoU against After
Effects (headline), IoU against ground truth, boundary distance, soft-edge
error, temporal stability, drift and time per frame, plus a proposed pass
bar left to the maintainers. Linked from docs/fidelity/README.md.
docs/gaps.md (#14) and docs/target-app-parity.md now list what landed and
leave the comparison as the one remaining item.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Measured against After Effects 26.3 with the original
examples/ae-spatial-tangents.jsx (three paths, ten keys, even and uneven
timing): an auto-Bezier key's out tangent is (next - previous) / 6 and
the in tangent its mirror, whatever the key times; an end key uses its
one neighbour, (neighbour - key) / 6. EffectCraft gave end keys none and
scaled middle tangents by segment length, so paths with auto-Bezier keys
ran up to 28 px from AE's. All ten tangents now match; path samples are
within 0.05 px.
Tests that relied on end keys having no tangent now expect AE's: Spatial
Bezier keeps auto keys' handles (linear keys still get a third), the
motion-path handle is drawn at a sixth, and a straight loopOut path is
compared within 1e-9. docs/fidelity records the method and scores.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
vangel76andClaude Opus 5.5
KattandClaude Opus 5.5
Vikram Bhaskaran
Dexter