Bone Bind / Weight Paint tool
Bind vertices to a bone by hand, or paint how strongly each vertex follows it.
The Bone Bind / Weight Paint tool (Shift+J) needs the scene's Bone layer to already have at least one bone in it: with none, the tool does nothing. Any editable Shape or Mesh layer in the scene can be bound, so you do not need to select the layer you are working on; you just need its vertices, and it needs to be editable.
Bind mode
With Weight Paint turned off, the tool works vertex by vertex: click near a bone to select it, click near a vertex on any editable layer to select it too: Shift adds more, otherwise the click replaces the vertex selection. Dragging an empty area marquees vertices, but only on layers already part of the layer selection.
| Enter | Bind the selected vertices to the selected bone, at full weight |
| U | Unbind the selected vertices from the selected bone |
Auto Weight distributes smooth weights automatically, scoped to the shapes that own your selected vertices (or to the selected layers if no vertices are picked) with up to four bones influencing each vertex. Weight Area recomputes just the selected bone's own weights from its influence radius, leaving every other bone's weights alone.
Link Layer rigidly attaches a whole layer to one bone's motion, as a shortcut for cases that do not need per-vertex weighting; the button relabels itself to Unlink once a layer is linked.
Weight Paint mode
Turn Weight Paint on to paint influence with a brush instead of binding vertices one at a time. Every editable vertex is shown as a heat-mapped dot, from blue at zero weight to red at full weight, so you can see the result as you paint.
| Option | Range | Default | What it does |
|---|---|---|---|
| Weight / Unweight | None | Weight | Whether the brush adds or removes influence |
| Radius | 5 to 300 (screen px) | 40 | Brush size |
| Strength | 1 to 100% | 50% | How much weight one stroke adds or removes |
| Falloff | Linear / Smooth / Hard | Linear | How weight tapers from the brush centre to its edge |
Hold Alt to erase weight for a stroke regardless of the Weight / Unweight setting. A pen's pressure scales the strength as you paint; a mouse always paints at full strength. Mirror Weights copies each bound vertex's weight onto its mirrored vertex, matched by bone name: a bone named with a .L suffix mirrors to its .R counterpart.