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Skin binding

Skin binding wires a Mesh3D placement to a joint chain so the mesh deforms when the joints move. The Designer's bind is a simple, distance-weighted skinning model that produces good results for the kinds of geometry shipped with skins.

Setup

  1. Position your joint chain where you want the mesh to bend.
  2. Select the Mesh3D placement.
  3. Shift-click the root joint of the chain (the topmost parent).
  4. Rigging > Bind Skin to Selected Mesh.

The Designer assigns each mesh vertex to one or more joints based on proximity and joint segment direction. After binding, moving any joint moves the mesh.

What "bind" stores

Each vertex gains a small weights table:

vertex 412:
  shoulder_L = 0.0
  elbow_L    = 0.18
  wrist_L    = 0.82

Weights sum to 1.0 per vertex. The framework computes the deformed position as a weighted blend of the joint transformations.

The default binding uses 4 weights per vertex; configurable up to 8 in Preferences > Rigging > Max Weights Per Vertex. More weights smooth the deformation but cost more per-frame compute.

Verify the bind

  1. Select the wrist joint.
  2. Rotate it 30° around its hinge axis.
  3. The mesh should follow smoothly.

If the mesh moves rigidly (no smooth bending) → the wrist's influence is too narrow; increase the bind radius.

If the mesh tears or stretches oddly → vertices are getting weight from the wrong joints; recompute with a smaller bind radius, or adjust by hand via Paint weights.

Bind options

Rigging > Bind Skin to Selected Mesh > Options… exposes:

Option Default Notes
Bind radius auto How far a joint's influence reaches; auto uses the joint segment length
Max weights 4 Per-vertex weight slots
Falloff inverse_distance_squared Distance metric
Heat map off Visualize per-vertex weight count

Heat map renders the mesh tinted by how many joints influence each vertex: blue (1 influence, rigid) → red (8 influences, very smooth). Useful for finding spots that need painting.

Apply Skin Deform

Rigging > Apply Skin Deform (from current joint pose) is destructive: it bakes the current deformed positions into the mesh's base vertices and removes the bind. Use to:

  • Lock in a pose as the new rest position.
  • Free the per-frame compute when the deformation is final.

This is the opposite of Reset Bind Pose; both are irreversible (short of undo).

Reset Bind Pose

Rigging > Reset Bind Pose returns every joint to the pose it was in when you ran Bind Skin. Useful when you have moved joints during animation and want to get back to the rest pose without manually keying every joint to zero.

Unbinding

Rigging > Unbind Skin removes the binding. The mesh stays where it is (in whatever deformed state it was at the time); joints revert to free transforms.

See also