Ragdoll Part4: ragdoll shapes follow target joints, visible joints follow ragdoll shapes

If you enable this option in the menu:   Developer -->Avatar_Options-->Collide_As_Ragdoll  then the avatar's skeleton's collision shapes will self collide and the visible positions of the joints will try to follow the positions of the skeleton's shapes.

To see the shapes being used for collisions enable:  Developer-->Avatar_Options-->Skeleton_Collision_Shapes.
For when we need to know the simplified "rotation of joint in its parent frame" we can use these methods.