I’ve been working on this character the last few days and I am very pleased with the modelling so I wanted to add a rig to it.
After building the rig (based on a human rig inhanced with some facialbones for the tong, ears and snout and a long tail) I tried parenting it to the model with automatic weights. and I got this error:
“Bone Heat Weighting: Failed to find solution for one or more bones”
The result was one huge disaster, all the bones were very lightly applied to every vertex of the mesh or none at all. So then I tried to parent them menually using the weightpaint, but that didn’t come out smooth either.
In a final burst of desperation I accepted the non-perfect bones and rigified the model. but the rig that was created didn’t have anything for the snout, tail or anything. and above that all the bones turned in a differend way then they were supposed to do. (bone axes have Z turned up)
Having to add the constraints manually I can life with, But can anyone please tell me how to fix the parenting with automatic weights? or what might be causing the problem?
If you’re working with Rigify, it might work better to just do the Rigify thing first, then add extra bones after. I think what you’re running into is that if you add bones to the ‘fit’ rig before hitting Generate, you’re confusing Rigify. It finds bones it doesn’t recognize and therefore doesn’t know what to do with them.
You can built any facial rigging separately and then use Ctrl-J to join that rig to the Rigify-generated rig.
The auto weighting works best on a single manifold mesh. Having multiple parts to your mesh is the most common cause for the error message you are getting. Try separating them as objects and then auto weight painting, and join after if you want them as a single mesh.
If you’re working with multiple meshes, each one will have to be parented to the rig individually, then weight painted.
Of course, if you know that one or more of those multiple meshes will only be affected by a single bone, you can pick the ‘Bone’ option instead of Automatic Weights. It’ll save you some time/headaches.