Oh, did I mention the hair was special with a combination of morphs and rigging?

Well, the hair has 20 (for now) all combinable morphs and is part of the head vertex group, and there are no hair specific vertex groups or bones.

The upper part is weightmap rigging controlled from the head and neck, and the lower part of the hair is weightmap controlled through the collar movement.

And, LOL, to keep things simple (ahum) the collar itself is controlled through the shoulder bone. I never "pose" a collar, because when we move our shoulders, the collars follows automatically. That is what this figure does too. => So? End result? ? ? ? ? When the arms are moved? ? ? ? The hair gradually follows and that is how we prevent intersections with movements. LOL.

That is how human anatomy, geometry, rigging and technology combines.

PS : The figure is a tech demonstrator, nothing more, nothing less.

Best regards, Tony