Rigging: Twist Solver

Hello,

Long time ago, I posted everywhere I could to ask for help to solve a simple issue of an IK forearm which didn't twist correctly in a specific pose. Indeed, due to Blender's Quaternion logic, even when the bone value is displayed in Euler, if the bone (here the hand) is oriented the opposite way, the rotations value will go crazy. and your forearm will switch from 89° to -270° directly, like in the example.

(Even Rigify seems to have the same issue if I try a similar pose, but it's harder to reproduce it in a realistic pose though)

So here is my request: Could you please add a "twist solver" option to the bones and / or bone constraints which could help to get a correct rotation?

This is really important for me, and for a lot of riggers as well I think. I love Blender, but I'm always feeling down when I see this problem and that there's no way I can fix it.

Thank you for your attention.

PS: And if it's not possible to add this option, I think that maybe you should think about converting the rotation system of Blender from Quaternion to Euler. I'm aware of the risks of Gimbal Locks for software using that kind of rotation, but as an animator, I can swear that I prefer to be cautious about Gimbal Locks rather than having to deal with those rotation jumps on specific poses. Though, I also know that it may be a lot of work to do, so if it is possible, adding a "Twist solver" option may be easier.

Animated gif of the issue: