paint mask
Rotoscoping by hand. Paint the region on a keyframe, paint it again later, and the app tweens between your strokes — the mask shaped exactly like your eye, not an algorithm’s guess.
What it’s for
Disney’s rotoscope artists traced over live footage frame by frame because no formula could find the line their eye found. The paint mask is that craft, kept honest by onion-skin and tweening. You paint the region on a keyframe, paint it again further along the timeline, and the app interpolates the shape between your two gestures.
brushSize sets the stroke width in grid cells,
from a fine edge to a broad fill. hardness
chooses between a feathered or a crisp boundary, and
opacity controls how strongly each stroke
commits. Set interpolate to tween between
keyframe paints, or turn it off for hard holds.
Reach for this when: you want a mask shaped exactly like that one specific gesture; an algorithm just won’t find what your eye does; the boundary is a creative decision, not a detection problem.
Where it lives in the app
Add from the Masks panel. The mask appears as its own layer
on the timeline; assign it to one or more effects by setting
their target to point at this mask layer.
Parameters
| Key | Range | Default | Effect |
|---|---|---|---|
brushSize | 1–20 cells | 3 | Brush size in grid cells |
hardness | 0–1 | 0.5 | Soft/hard edge |
opacity | 0–1 | 1 | Brush opacity |
interpolate | 0 or 1 | 1 | Tween between keyframe paints |
Pairs well with
- color grade — relight exactly the patch you painted, the way a colourist windows a face by hand.
- text-glitch — confine the breakdown to a shape only a human would have chosen. Deliberate, not procedural.
- chromatic aberration — fringing inside a hand-drawn region, so the wobble feels authored rather than accidental.
- phosphor CRT glow — a painted highlight that blooms like something you decided should be the brightest thing in the frame.