I was just wondering how everyone manages their shoulder rigging. Do you make a seperate bone for the shoulder and weight paint it? Do you just add the shoulder to the upper arm bone vertex group?
See first and second pic for upperarm and shoulder weight paint, third pic for deformation result.
Here’s a recent post about that subject:
A couple other thoughts… When I weight paint, I like to turn off subsurf, use ‘set solid’ (or flat shading depending which version of blender you use), and enable wireframe in addition to solid for the mesh. These allow you to see the actual mesh as you weight paint it.
Can you post a screenshot without smooth shading & subsurf, and with solid and wireframe enabled for the mesh of the shoulder area? I find it easier to see the topology this way.
But yea, read thru that link, some good stuff & links posted there.
Edit: I just was looking again at your pictures, is the shoulder bone part of the arm IK chain? You might want to try positioning the root of that bone so it’s a bit more horizontal, and use more weight paint on it. But I don’t know what other bones are affecting that area…