When creating anatomical teaching materials, it would be nice to highlight different structures with different colors. Obviously this is best done with segmentation, but that’s quite a lot of work; especially when all you want to is highlight an external surface. Closed curve in this situation would work really well, but it needs to also cover the inside of the polygon (but with about 50% opacity), not just the boundary.
Is there a piece of python code to do that? Or better yet, can this be a property of the closed curves?