Crucible
How to pull a matte on a shot that never saw a screen.
Crucible
The matte engine: comp-grade mattes with true float alpha, for hair, motion blur and soft edges. Arm ✛, click the subject in the viewer (Alt+click to push a wrong region back out), then 🜛 Analyze — it identifies at every frame you clicked, propagates across the range, mattes the edge, and takes the old background's colour out of it. The matte lands in alpha and on its own crucible channels; RGB is untouched. It will not guess: with no clicks it does nothing and says so. ⟲ To Roto turns the result into an ordinary Roto node when you want to take over by hand.
CrucibleRefine
Matte finishing for ANY alpha — a keyer's, a roto's, an imported matte, or one Crucible made. Clean the haze out of black and white, feather or sharpen, tighten contrast, shift the edge, grow or erode just the solid core. Shift Edge is the one to know: it translates the soft profile along its own gradient instead of eroding, so nudging a feathered edge keeps the falloff you spent time on. Every knob is a no-op at its default.
Getting started
- Drop a Crucible on the plate and view it.
- Click the subject. The engine segments it and shows the matte.
- Where it is wrong, correct rather than re-run: the correction vocabulary below decides which tool to reach for.
- Chain a CrucibleRefine when the edge needs separate treatment from the region.
How it works
Crucible runs as a staged pipeline — a colour model, a flow-warped propagation, a segmentation stage, and a refinement — with the artist's edits carried as an edit ledger beside it. Nothing you do overwrites the solve; edits bias it, and the solve is re-run from them. That is what makes a matte correctable a week later on a machine that never saw your session.
Segmentation runs on our own SAM 2 export (hiera-small).
The correction vocabulary
The disambiguation rule is a requirement, not advice — it is what stops four tools from all half-working on the same problem:
| The matte is wrong because | Reach for |
|---|---|
| it found the wrong object | Fix |
| it has the wrong shape | Guide |
| the softness is wrong | Refine |
| it should never have looked there | Exclude |