Is it true to say that voronoi shatters always result in polyhedral shapes, and no convex or concave (polygon shapes) at all?
thanks
Jack

I don't understand the question.

Are you are asking whether there are always flat poly edges rather than curved, if so, yup I believe so. I've not done 3d but I assume it is the same as 2d. They should all be convex.

https://en.wikipedia.org/wiki/Voronoi_diagram

Voronoi cells can be concave as well, depending on the distance metric function chosen. Euclidean distance gives convex results, but Manhattan distance, for example, may not.