If you connect with lines all the points of a random 3d point-cloud, you get the wireframe of many irregular tetrahedra that don't overlap and are adjacent to each other (if the points aren't coplanar). I want find out which points of the point-cloud correspond to the 4 vertices that belong to the tetrahedron that contains a given point in space (taken from a second set of points inside the main point-cloud). I'm looking at 'Delaunay tetrahedralization' but there has to be a simpler method that i didn't thought about. http://grasshopper3d.googlegroups.com/web/pointcloud-tetrahedra.jpg
