in unreal Engine you can work with 'component' jaw pitch and roll witch acts pretty much like the 'object' or 'local' rotation mode in maya when rotating an object with the gizmo. Adding or subtracting rotations will not result in gimbal locks and convert to euler behind the screens, this will be more straight forward for rigging.
Please add some native nodes that can return the component jaw pitch and roll which you can convert to quats, euler (rotation order), matrix etc. and vise versa.
This should make twist calculations more easy to implement and rigging more fun. The roll of your wrist will then be the simple twist amount of your twist joints in the arm, very easy to implement.
lets say a shoulder corrective, a few nodes to negate the arm roll and do a - 50 % of pitch and yaw.
Also please implement a simple arc, cos, tan, etc node. this is a very basic math node that is missing.
look here (https://www.chadvernon.com/blog/trig-maya/) at how ridiculously complex this is to make something as simple as that.
Also make commands for this in cmds.xform to get the roll jaw and pitch
also see
https://vaishakp.com/2018/05/28/angle-extractor-in-maya/
https://vimeo.com/122797330
https://apps.autodesk.com/MAYA/en/Detail/Index?id=1642215970322859153&appLang=en&os=Win64
thank you
Tristan
