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Vector Warp

How to paint once and carry it through the shot.

BS_VectorBake

Analyses the plate once: dense vectors at frame distances 1..64, forward and back, each with a baked CONFIDENCE plane (Nuke bakes none), written to EXR beside the project. Wire an optional matte to exclude a subject. Then warp anywhere with BS_VectorWarp.

BS_VectorWarp

SmartVector-class propagation: pick a reference frame, paint on it, and this carries the patch to every frame through the bake — routing on confidence around bad flow, composing ONE map, filtering once. Wire a matte and the route is judged over THAT region only. Outputs warped / stmap / confidence / error (the round-trip heatmap: green comes home, red slips, blue left frame — read it BEFORE painting to pick the reference frame). Occluded pixels hold and fade instead of smearing; `untrackable` marks spans the solver must hop over rather than walk through; `edge` says whether a route leaving the plate fades (default) or drags the border in. List several frames in `references` and each pixel takes whichever route was most confident — the keymix rig Foundry's own docs tell you to build, in one node; the `winner` view colours who owns what.

Getting started

  1. Drop a BS_VectorBake on the plate and press ⚒ Bake. It writes every frame's vectors — at distances 1…64, forward and back, each with a confidence plane — beside the project.
  2. Point a BS_VectorWarp at that bake, pick a reference frame, and paint your patch on it.
  3. Set output to error before you paint and read the heatmap: green comes home, red slips, blue left frame. Move the patch, or pick another reference frame, while it is still cheap.
  4. Premultiply, merge, regrain.

How it works

Three decisions carry the whole system:

  • The route is solved, not assumed. To get from the reference to this frame, the solver takes the chain of baked hops that accumulates the least error — a shortest path over the frame graph weighted by baked confidence, so it routes *around* a bad stretch by taking a longer hop over it. Foundry solved this once at design time; baked confidence lets us solve it per shot, per region.
  • Coordinates concatenate, images do not. The chain composes into ONE map and the source is filtered once. Sixty image resamples are the historical soupy failure; sixty coordinate lookups are not.
  • Confidence rides along. Below the floor the map holds rather than drags, the pixel is flagged in the confidence output, and the patch can fade there instead of smearing.

Workflows

GoalSteps
Remove a rig for the shotBake → read the error heatmap → paint on the best frame → warp → regrain
A shot too long for one patchList several references, turn on morph_keys, and paint a key wherever it starts to slip
A subject that passes behind somethingMark the span in untrackable — the solver hops over it and re-acquires on the far side
A patch that leaves frameLeave edge on fade: the alternative is the border dragging inward

Known edges