You create a bone, set it to rotate, and then within an "Action" timeline, you manually warp the vector art to look perfect at the extreme angle (e.g., arm flexed). When you rotate the bone in the main timeline, the software intelligently morphs between your key shapes.

Anime Studio Pro 11

You create a bone, set it to rotate, and then within an "Action" timeline, you manually warp the vector art to look perfect at the extreme angle (e.g., arm flexed). When you rotate the bone in the main timeline, the software intelligently morphs between your key shapes.