Is it possible to isolate parts of an armature so the mesh will never deform?

Question

I'm attempting to create a turtle character. I'm new to rigging & animation, so apologies if this doesn't make sense.

Everything has been pretty straightforward thus far, but I'm having problems with the weights. I did the rigging, and then set the meshes to have it as a parent with automatic weights.

I thought that I could paint the weights by bone, but it looks like it's only possible to do so by the whole armature (at least from what I can tell). My goal is to have the shell be completely rigid, and not deform with the rest of the limb movements. However, I still want the shell to be animatable so it can jostle around and such, just not deform like a traditional body.

Is it possible to isolate the shell? Maybe multiple armatures or some feature I'm missing? My goal is to export this as an FBX to Unity, if that has any bearing.

Any input is appreciated.

Answer 1

You could select the shell in Edit mode, go in the Properties panel > Data > Vertex Groups, on the right of the vertex groups list, click on the down arrow button and choose Remove From All Groups. You could now assign these vertices to your big body bone vertex group, or create a new bone, child of this big bone, give it a name, create a vertex group with the same name and assign your shell to it, so that you have a bone completely dedicated to the shell, if you ever need it to move slightly differently sometimes.

You say "I thought that I could paint the weights by bone, but it looks like it's only possible to do so by the whole armature (at least from what I can tell)", I'm not sure what you're saying, maybe you're missing that if you switch your armature to Pose mode, then select your mesh and switch to Weight Paint mode, you can select one bone and see what influence (i.e. vertices groups) it has on the mesh.