Here is an implementation of 3D alpha shape, it is using 3D DelaunayCell (standard GH component ??).
I liked a lot the explanation of Alpha Shape of CGAL site “Imagine a huge mass of ice-cream making up the space R3R3 and containing the points as “hard” chocolate pieces. Using one of these sphere-formed ice-cream spoons, we carve out all parts of the ice-cream block we can reach without bumping into chocolate pieces, thereby even carving out holes in the inside”
The little sphere gives the size of the “spoon”
The script has 2 flavors, one single CPU and one Multithreaded (2-4 times faster with 8 CPU)