Bone constrained to mesh via "child of" constraint does not deform the same mesh properly through hook modifier
Closed, ArchivedPublic

Description

System Information
W7x64 GTX680

Blender Version
Broken: 2.70a release
Worked: (optional)

Short description of error
Bone constrained to mesh via "child of" constraint does not deform the same mesh properly through hook modifier. Any attempt to move it around fails.
I was trying to have a single bone follow the surface of a mesh to add quick corrections after posing it (similar to clusters in Maya). I constrained it with a "child of" constraint (with vertex group so it follows four vertices specifically) and had it influence the mesh through a hook modifier. The hook modifier comes after the armature modifier.

Exact steps for others to reproduce the error

  1. Open .blend () -> hook bone appears at strange position (armature origin, in fact) below the mesh. Clearing transforms many times consecutively eventually resets it to its bind position (the one set in edit mode). Saving the file seems to have no effect, as each time it is reopened the bone will jump back to this position.
  2. Move one of the other bones (they are part of a different armature and deform the mesh through an armature modifier) => the "hook bone" jumps around weirdly.

Details

Type
Bug
Bastien Montagne (mont29) closed this task as Archived.Jun 14 2014, 1:19 PM
Bastien Montagne (mont29) claimed this task.

That’s not really a bug, by using the vgroup you are creating a dependency cycle (mesh -> bone -> mesh). Don’t think this will ever be supported actually.

Dependency cycle detected:
  MESH depends on ADJUST through Hook Modifier.
  ADJUST depends on MESH through Child Of.