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Paint weights

After skin binding, per-vertex weights determine how much each joint influences each vertex. The auto-bind gives sensible defaults; paint weights is the tool for fixing the spots it gets wrong.

Set the active joint

Rigging > Paint Weights > Set Active Joint (from selection). With a joint selected, this tells the painter "the next strokes write this joint's weights."

The View Panel tints the mesh by current weight: black = 0 influence, white = 1.0 influence, in between = partial.

Paint

Three painting modes:

Mode Menu / Hotkey Effect
Normal Rigging > Paint Weights > Paint at Cursor Stamp weight = brush opacity
Strong Rigging > Paint Weights > Paint at Cursor (strong) Stamp weight = 1.0 regardless of opacity
Reset Rigging > Paint Weights > Reset to Uniform (0.5 / 0.5) Reset selected vertices to balanced between two joints

The Brush tool's size + opacity in the Tool Properties dock control the painting strength. Use a soft brush for smooth blends, a hard brush for sharp boundaries.

Verify mid-paint

A handy trick: pose the joint to a deformed position before painting. The mesh deforms with the current weights, so you can see in real time how your paint changes the deformation.

  1. Pose the joint chain via IK / FK to the most extreme pose you care about.
  2. Switch to Paint Weights.
  3. Brush vertices that look wrong; the mesh updates live.
  4. Reset the pose when done.

Weight constraints

Weights are subject to two constraints:

  • Per-vertex weights sum to 1.0 (the painter normalizes automatically).
  • Max-weights-per-vertex caps how many joints can have non-zero weight (default 4; configurable to 8). Painting a fifth joint's weight onto an already-full vertex pushes out the smallest influencing joint.

Mirror weights

For symmetric rigs, paint one side and mirror to the other:

Rigging > Paint Weights > Mirror Weights Across X.

The mirror copies weights from positive-X joints to their _R counterparts (or whatever your mirror naming convention is in Preferences > Rigging > Mirror Naming).

Smooth

Rigging > Paint Weights > Smooth Selected averages weights between a vertex and its neighbors. Run a few times to soften a hard boundary between two joints' influence zones.

Heat map

The same heat-map overlay from Skin binding helps find vertices that ended up with too many or too few influences. Toggle with View > Skin Weight Heat Map.

Performance

Painting on a 10,000-vertex mesh runs at full pen frame rate (120 Hz tablets, 60 Hz mice). The Designer batches weight updates per stroke so the GPU stays warm.

See also