Bad distortions after copying bone transforms

hello friends, I have a model of the hand that I’m animating based on imported mocap files. The process of copying the animation from an imported armature to my armature is described in this answer:

In short, there are three steps:

  1. Create constraints and link bones between two armatures
  2. Iterate over all frames, apply transform, and insert keyframes for all bones
  3. Delete constrains

The problem is that after this process the weight painting of the hand is all messed up, causing horrendous distortions of the hand:


When I examine the weight painting, the one on the rest position looks nice, whereas the one on the pose position is not good.

What is going on? How can I make sure the proper weight painting is respected?

The weight painting on the rest pose and deformed model is the same, trust me. You’re chasing a red herring.

Find the frame where the pose starts to look bad, then upload a file. At the (1) step above: you have the constraints to copy the mocap, but you haven’t written them to bone transforms yet.

It could be rig constraints, it could be some issues with how you’re copying transforms (to the wrong bone, for example), it could even be weights (but again, they’re the same weights in pose as in rest, an armature doesn’t change a mesh’s weights.)

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You are right. I found that the bone axes are inconsistent across the armatures. I rigged the model using an armature with a certain axis orientation and the imported armature has a different one, so the transforms don’t match and that’s what’s causing the problems. Thank you.