Here are two bone rigs. One on the left is just a 2 bone armature. One on the right is a rigify generated skeleton. Both meshes are skinned and hard weighted to two joints (no blending of weights). However when the knee joint is bent, the mesh on the right is “bending” vs. being straight??? Is there some vodoo that happens to rigify bone skin weights that blends across joints regardless of the painted weights? :spin:
You’ve failed to supply the .blend file so we don’t have access to the other important info you missed out from your post
Is a blend file required to post an issue to the forums? If you require a blend file then why not just post the issue and then add a request comment for a .blend file? I posted this two days ago
Anyways, I was able to figure it out on my own:
This problem resulted from an underlying base Rigify skeletal hierarchy being modified via script (for game engine use). It turns out that four of the skeletal bones (shin-1 and forearm-1) have their curved bones set for 16 segments under the armature/bone/deform settings. These settings round out the mesh adding to the skinning information and preventing a hard edge between vertex group weighting.
FIX: Under the bone properties panel, expand the deform tab and on the right side you will see the curved bones section:
These settings need to be switched from Sections:16, EaseIn:1, EaseOut:0 (defualt Rigify) to Segments:1, Ease In:1, Ease Out: 1 on both shin-1 and forearm-1 bones. This will remove the bending seen in the original post.