I am using Rigify on Blender 3.6.1 with the Wolf armature to rig a dog model. All was going well until I noticed that the two DEF-front_foot bones are rotated about 45 degrees. The rotation of the bones are distorting the mesh.
The DEF-front_foot bones are aligned perfectly in edit mode. But when I switch to object or pose mode they are rotated.
I can’t figure out how to correct this. The corresponding bone in the metarig has a correct roll of zero. The problem appears to be similar to the one in this thread: https://blenderartists.org/t/rigify-bone-rotation-issue/1100878. That poster was able to fix the problem by correcting the bone roll. But as I mentioned, the bone roll here does not seem to be the issue.
Regenerating the rig doesn’t fix the problem. Deleting all traces of the rig and original metarig, and creating a new metarig from scratch, does fix it. So I could just rebuild and reweight the rig. But I’d like to avoid that if possible.
This is the generated rig? If so, did you already try also correcting the bone roll of any control bones that are used in the constraints on the deformer bone? Since it’s fine in edit mode, I would guess that the problem comes in with the constraints and the associated bones.
Yes, it does have something to do with the control bones front_foot_tweak.R and .L. They are rotated out of position, but snap back into place when “Inherit Rotation” is disabled.
Which seems counterintuitive to me. The parent bones, front_foot_tweak.R and .L, are rotated properly. Enabling “Inherit Rotation” on their children causes them to be out of alignment. Disabling it puts them into alignment. Is this correct?
There are no constraints on front_foot_tweak.R and .L.
EDIT: As a test I inserted a Wolf metarig into a new, empty scene, and generated a rig. Everything is as expected. The two control bones are aligned properly and “Inherit Rotation” is enabled.
Could something else be affecting the rotation of the control bones in my original scene?
So I tried generating my own wolf rig, and I reproduced what looks like your error by messing with the roll of this MCH-front_foot_tweak.R.001 bone. Adding 45d to it’s roll gave me results similar to yours, including the checking and unchecking inherit rotation. If you find MCH-front_foot_tweak.R.001 in your rig, what’s its roll? Default seems to be 174 degrees, but might vary depending on how much you adjusted the base rig. You could try adjusting that bone and see if it fixes the issue.
Beyond that I’m not sure what might cause the problem. If adjusting MCH-front_foot_tweak.R.001 doesn’t fix it for you, you can try linking the file, and if I can’t find the problem with it, you’ll probably have better luck finding someone who can, if they have the real thing to work from.
Brilliant. That was it. The rotation of those bones was off by about 50 degrees. I just set them to match the rotation of the parents and that fixed the problem. There is still a tiny wobble when I enable/disable “Inherit Rotation,” but it’s too small to mean anything. I’ll take a closer look tomorrow.
Thank you! You’ve saved me several hours work reweighting the mesh. And now I have a better idea of how to go about troubleshooting these sorts of things.
