I'm trying to setup a rig that allows IK/FK (via influence property), where the forearm twist joint automatically alleviates part of the twist of the hand. Not necessarily as part of the IK - just something that makes the wrist help the hand twist, automatically.
So I have this setup:
Shoulder -> Elbow -> Wrist -> Hand ..where Elbow & Wrist are the same forearm bone, with a single twist rotation in between them.
So when the hand twists along its length axis (for either FK or IK), I would like to make the wrist automatically twist along that same axis. I would be fine if the wrist assumes 100% of that rotation, but would rather be able to customize the amount it rotates.
Has anyone setup something like this? Or do you typically just manually alleviate the twisting of the wrist by adjusting the bones on each frame of animation?
My character will be exported for the Unreal engine, so I am limited in the types of bones and solutions I can use. I'm pretty sure bendy bones won't work for me. I've tried simply adding a driver to the wrist bone to make it assume some of the rotation of the hand in the appropriate axis. But I also have the IK constraint applied to that same (wrist) bone, which apparently causes very bad transform issues. The mesh ends up stretching and exploding in that area.
I'm trying to find a solution and will post it on here if I do before anyone can help.