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Aphelion

Aphelion Editor

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7 — Roto and masks

Draw keyframed shape masks for garbage mattes and rotoscoping, then combine them with tracked or keyed mattes.

You will build: a Roto node whose mask output reveals a graded version of the plate.

Steps

  1. Add a Roto node (Tab → Roto). It has no frame input — a Roto shape is a generated matte.
  2. Turn on Roto → Edit Mode. The viewport overlay becomes editable and the Properties panel shows the shape controls.
  3. Draw your shape in the viewport (click to add points, drag points to move, drag a segment to add a point).
  4. Scrub to a later frame and move the points to match the subject — the shape is keyframed automatically as you edit. Move the playhead before every edit so each pose lands on the right frame.
  5. Turn off Roto → Edit Mode to lock the shape and go back to navigating.

Roto → Invert swaps inside for outside (useful for garbage mattes that should exclude a region rather than include it).

Using the matte

A Roto outputs a single mask socket:

flowchart LR
    VI[Video Input] --> CG[Color Grading]
    VI --> MG[Merge]
    CG --> MG
    RO[Roto] -- mask --> MG
    MG --> V[Viewer]
  • background = the ungraded plate, foreground = the graded plate, mask = the Roto. The grade appears only inside the shape.
  • Or invert it and use the shape as a garbage matte to exclude a rig, boom, or tracking marker before a key.

Combining with other mattes

Use Matte Combine Pro to merge a Roto with a Chroma Key or Shape Tracker mask:

  1. Chroma Key.mask → Matte Combine Pro.a
  2. Roto.mask → Matte Combine Pro.b
  3. Combine → Mode = Union (add), Subtract, or Intersect as needed.
  4. Feed the combined mask into a Merge.

Combine Masks does the same job with a simpler mode list.