I was stuck quite a bit trying to get a good wrist and forearm twist. IK upvectors weren’t cutting it. I couldn’t offset (without drivers) the IK pole. Nore could I have proper rotation constraints.. it seems Euler is just.. a concept and all bone rotaiton is ultimately in Quaternian. Local also isn’t really a thing, as rotations still work globally – meaning on elbow bend and shoulder bend, I was getting terrible gimbal lock and weird offsets on rotation.
This is one thing in the Blender core that I am nooo fan of. Softimage defines and reads out and controls Global and Local matrices as they are, as they should be, fully controllable, seperate, agnostic, and as they are, local according to bone/object axis origin, global to world center. In Blender there is no clear definition of one or the other. You can’t control Global then Local with unique transform modes, and you can’t drive one or the other properly. Things inherit Global/Local matrice control without any UI feedback nor definitive values whatsoever. You think you move in local, rotate a bone origin in local, then discover that the rotation gimbal is set to a global quaternian or euler that causes a gimbal lock.
So.. I had to work around.. and I found that nature has the solutions, and then proceeded to make a double forearm bone to create the twist. It worked. I should have done it this way since forever. So happy to now know! It also could work in other software.
:dance: