Alpha shapes in 3D

Question

Is there an \"alpha shape\" function in 3 dimensions in python, other than the CGAL python bindings?

Alternatively, is there a way to extend the example below into 3D? <

Answer 1

You are looking for a "concave hull". The marching cube algorithm can be used to find such a hull. You can find a full example here.

Limitations: This approach works well if your data comes from a volumetric dataset or if you have a cloud of points that can easily be converted into a volumetric data set (voxel-like). This can be done relatively easily with a dense set of points using, for example, a spatial indexer like the scipy cKDTree, but you might end up scratching your head a bit to get a good result if you have a sparse cloud of points.