Alexander Gavrilov
b5c3f26cba
The double quaternion blending method in addition to the deformation matrix of each bone requires their rest matrices. For ordinary bones this literally should use the bone rest matrix without any ambiguity. However, it was also using the bone rest matrix for all of its B-Bone segments, which is incorrect and causes strange deformation in some cases involving extreme non-uniform scale, especially at boundaries between different B-Bones. There is also a similar known issue that happens with scale at bending joints, and this fix reduces the distortion when both bones are B-Bones. This changes both the Armature modifier and the Armature constraint to use the actual segment rest matrices. Unlike bones, these can have scale even in rest pose, so normalization is required. Differential Revision: https://developer.blender.org/D10003