Twisting arm deformations

Hello, all! My most recent Blender project has been to fully model and rig a low-poly human. However, when I modeled him, the arms needed to be turned around to face him. So, the problem I ended up having was that whenever I turned the arm bone around, it twisted his vertices in an ugly fashion. I’ll attach some pictures to try to express my issue. By the way, I used Rigify to create the rig for my mesh.


Any help is appreciated. Thank you!

Rigify uses a two bone deformation system to isolate the twisting and allow better deformations when twisting. Auto weighting will never look good with this system. Some cleanup is needed.

Here is a list of Rigify tutorials that will show you how to fix this issue. https://blenderartists.org/forum/showthread.php?404318-Rigging-with-Rigify

Good luck!