CGAL users discussion list

[Noel Warren <>]

I've spent ages on this problem.  After a few boolean operation I have a Nef_polyhedron_3 with various volumes.  I now need to do two things

1)  I need to create new Nefs, each representing a volume of the original.

2) Also with these new nefs I need to triangulate their surfaces and get the raw coordinates. The off file format will do me fine in this case

The second seems relatively straight forward.  Just convert my Nefs to normal Polyhedrons and then just stream them out.  This only works if they are simple so my first requirement should output valid Nefs, ignoring stray faces, lines, vertices and planes.

I have tried various approaches for my first requirement, most notably the convert_inner_shell_to_polyhedron function, which I found to be quite temperamental.  More often than not it would fail with messages like

CGAL::Polyhedron_incremental_builder_3<HDS>::

lookup_halfedge(): input error: facet 3 shares a halfedge from vertex 1 to vertex 2 with facet 0.

I'm on CGAL 3.9.  Has CGAL 4 solved this issue?