I’m super new to rigging and this was my first rig on a model that I’ve made. I’m trying to rig this skeletal arm to move and rotate just as it would irl. So far, I’ve got most of the rigging functioning properly but the ulna/radius rotation (bones in the forearm) is super tricky. I’ve spent hours already and can’t figure out how to get the wrist to rotate with those bones correctly. When the wrist rotates I don’t want the ulna (forearm bone closer to the pinkie) to be rotating with it, I only want the radius bone (forearm bone closer to the thumb) to be rotating. Here’s a reference video for what I’m trying to accomplish: https://youtu.be/eS40-cQU8BM?t=54.
I originally had the ulna and radius parented to a single forearm bone but that’s not going to work for the rotation I’m trying to get. The problem is if I separate them into two separate bones, I’m not really sure how I’ll get the up/down rotation of the forearm to be synchronized for the ulna and radius while separating the movements of the two bones for pronation/supination of the hand. Any help would be appreciated, thank you!!!