CGAL users discussion list

[Josh Stratton <>]

I had a quick question regarding the half-edge data structure present
in CGAL.  I've read over the documentation several times and
understand that the mesh must be 2-manifold and doesn't support holes
inside facets, which is fine.  What I couldn't find however, was
whether the structure supports singular vertices, where one vertex is
attached to multiple non-joining facets.

*---*---*
|     |    |
*---*---*
|     |    |
*---*---*



*---*
|     |
*---*---*
      |    |
      *---*

For the vertex in the middle bridging the two facets, it will only
point to an edge on one of the two faces.  Looking over the API, I
don't see anything that allows lookup of the other face given just the
vertex.  Is this not a supported mesh configuration in CGAL's
half-edge implementation, or is it okay, but requires additional code
to handle these cases?