CGAL users discussion list

[Olivier Devillers <>]

>  constrain all the edges
>  of [a] polyhedron and you have constrained its faces…

No,
consider 2 regular tetrahedra glued by one face.
you have a polyhedron with 6 faces,  5 vertices, you can ask to 
constrained the 9 convex hull edges
but there is still two possible triangulations
(the two tetrahedra or 3 tetrahedra around a central edge)

Thus constraining  all the edges of the gluing face does not guarantee 
the existence of this face.


But I actually answer too fast, it is not possible to constrained the 
edges of the
Schönhardt polyhedron. What it is always possible is to conform it.

i.e. you can add points on the edges of any  set of constrained edges 
such that the constrained edges
belongs to the Delaunay triangulation (but they are splitted). It is not 
possible to add points inside a set of
faces to get a similar result.