copying vert positions relative to skinned joint

[s...@weacceptyou.com]

Hi there,

i have two 3d scan character meshes that have been skinned, one is a neutral male pose, the other is a male with his arms bent in 'muscle man' pose.

the topo is identical, the relative joint placement should be identical.

what i want to achieve is to copy, for example, the forearm verts (those verts that are assigned to the forearm joint after skin weigths painting) of the 'muscle man' pose and apply the position of these verts to the neutral man forearm.

But it needs to get and set the vert coords relative to the forearm joint, in its local space. That way the world position and orientation would be aligning correctly.

this is so i can use the muscle deformation present in the 'muscle man' scan and apply it to the neutral scan as a blend shape, then i can blend into that morph target when i raise the arm and it wont double transform.

does this make any sense? any help on how i could do the maths of this would be very helpful.

thanks,
Sam