I think it looks like Hype Physics supports rounded edges (Chamfering)
This thread is confusing to me, so I'm not sure what's being asked. But as an example, if you wanted to create pizza slices as physics shapes, one of the corners could be rounded with the Border rounding option in Hype. The image would then have to be positioned to match the shape, but that's a way to get customized collision shapes.
I typically use Photoshop / Pixelmator to edit images. I'm not too familiar with c4d.