Problem: Object Matte computed its frames only on demand while rendering, so
playing a shot stalled on every untracked frame, there was no progress or way
to stop, and nothing kept the mattes once computed.
Fix: Object Matte runs through Roto Brush's job machinery (one job slot,
cancellable with roto.cancel, a worker thread on the desktop, a Web Worker in
the browser, never the UI thread). objectMatte.propagate computes the frames
around the reference frame (clipped to the layer) outward, filling the same
content-keyed segmentation cache the renderer reads; the engine's sync now
queues an instance for background tracking when its frames or prompt change.
objectMatte.freeze stores the final mattes in a new hidden Frozen parameter
(Roto Brush's FrozenCache format) under a key of the input, prompt, span,
model and matte settings; renders use them without segmenting while the key
matches; a frozen prompt is refused until objectMatte.unfreeze. Freeze is one
undo step and is dropped if the prompt changed meanwhile.
objectMatte.status reports progress, frozen state and computed frames. Effect
Controls shows Freeze / Unfreeze and Track / Stop with a status line (progress
banner). The frontend now polls Roto Brush / Object Matte jobs on their own:
before, a finished job (and so a Freeze result) was only picked up while a
Warp Stabilizer job was active. Job progress is set before the worker starts.
Tests: engine tests_roto::object_matte_background_job_cancel_and_freeze
(queued by the edit, returns at once with progress, cancel keeps a partial
result, completion computes all 25 frames, frozen renders recompute nothing,
unfreeze recomputes, undo restores); effects object_matte job_frames and
frozen-matte tests (stored pattern used, key mismatch and damaged data
ignored); ui-egui ui_object_matte Effect Controls Freeze end to end.
docs/agents.md: Object Matte section; docs/effects.md regenerated.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Problem: Object Matte could only be applied through the objectMatte.apply
command; After Effects 26.2 picks the object directly in the viewer (click it,
or drag a box around it).
Fix: an Object Matte tool (with Roto Brush & Refine Edge in the Alt+W slot,
icon drawn in code). In the Composition viewer a click sets a point prompt and
a drag a box prompt (its centre the point) on the footage, solid or comp layer
under the pointer, converted to layer pixels through the layer's transform.
The layer's Object Matte (the selected one, else its last) is re-prompted;
Shift adds another. Everything goes through objectMatte.apply, which gained
`effect` to re-prompt an instance (point, box or no box, reference frame; the
reach kept unless given), so each prompt is one undo step; the effect is then
selected, so its point controls show in the viewer. Hover draws a crosshair
and the outline of the layer that would get the matte (a live matte preview
would need a segmentation per pointer move). Automation ids:
viewer.objectMatte.crosshair / .target / .box, tools.ObjectMatte.
Tests: ui-egui ui_object_matte (hover, click, drag box re-prompts the same
effect, Shift-click adds one, undo steps); engine
tests_roto::object_matte_reprompt_updates_the_instance. Checked with the
headless snapshot example (hover crosshair, box drag isolating a disk).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Problem: with a trained model installed, Object Matte's optional box reached
MobileSAM only as background points along the box's edges (an approximation),
although the model's prompt encoder takes a box prompt directly.
Fix: a new Roto Brush stroke kind, Box (two opposite corners), that
stroke_prompt turns into the model prompt's bbox (scaled to the matte grid,
corners in any order, degenerate or non-finite boxes ignored). The graph cut
never rasterizes it. Object Matte emits it instead of the edge strokes when a
model segments; the classical fallback keeps the edge strokes. A prior matte's
box no longer replaces a box the user drew on that frame.
Tests: effects object_matte::the_box_reaches_the_model_as_a_box_prompt (a
stand-in model sees the box, at full and half resolution, and no edge points);
track roto::tests::box_stroke_is_the_model_box_prompt.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Problem: After Effects 26.2's Object Matte (pick an object with a click,
optionally a box, get a matte that follows it) had no counterpart; only
stroke-driven Roto Brush existed.
Fix: an Object Matte effect (Effect > Matte, ec.matte.objectmatte) turns
the Object Point (and optional box) on a Reference Frame into Roto Brush
strokes and segments them with Roto Brush's engine, content-keyed cache
and the model chosen in Settings > Roto Brush (MobileSAM, classical graph
cut without it). Track Object carries the matte frame by frame up to 600
frames each way; otherwise every frame is segmented on its own. Feather,
Contrast, Shift Edge, Invert and a Matte view. The engine keeps its Input
Key current so upstream edits recompute it. objectMatte.apply creates one
from agents / the CLI. Unusable prompts pass the layer through.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
