Rotating bone shrinks mesh

Hi all!

I’m almost a total noob in rigging & posing and I have already encountered a problem I don’t know how to solve. I’m using Blender 2.58.1 and I’m rigging a foot. I’ve modeled it, named vertex groups, created an armature, extruded various bones, named the bones accordingly to vertex groups they need to modify and created an armature modifier for the mesh. I haven’t touched any other settings for the armature or bones.

Now the situation is that the bones properly rotate the various joints, except the last one (the claw), which doesn’t rotate accordingly and the more you rotate the bone, the more the mesh shrinks (top two pictures, first is rest mode, second rotated). The bottom two pictures show how the previous bone in the chain properly rotates the assigned mesh.

Why is this caused and how can I solve it? Also, can you suggest some good rigging & posing tutorials for a beginner for Blender 2.5, that cover the basics and explain good practices?

Ok, “I” solved it, with a helpful hint of a fellow blender artist. :slight_smile:

Apparently the cause for this strange behavior is that the vertices in question belonged to two vert groups, each assigned to a different bone.

So I guess the morale is that for the purpose of bone assignment, you shouldn’t have overlapping vert groups.

1 Like

No worries…

You can have overlapping vertex groups, but you’ll need to play with the weights.

Yep, got it. Thanks again!