When animating CC3 characters, it seems like the clavicle bone is a little short. When the arms are hanging down by the body, it clips within the chest. If I move the arms a bit out, up and back, it makes the chest looks very prominant and massive (_03, _04). This is happening with both mocap data, and Mixamo data.

This is the mixamo idle: https://www.mixamo.com/#/?page=1&query=idle

Picture _09 is the first angle where there's no body clipping. I think this could easily be fixed if the clavicle bone is longer.