CGAL users discussion list

[Olivier Devillers <>]

> is it true that every boundary face of finite tetrahedra are 
connected to the infinite vertex by a (different) infinite cell?

every face of the convex hull is connected to the infinite vertex by an 
infinite cell.


The way the infinite cells are found is by exploring the neighboring 
cells from one infinite cell.


If you have an incorrect triangulation with
2 finite tetrahedra A and B
4 infinite tetrahedra around A
4 inifinite tetrahedra around B
(which is my feeling, but I am not familiar with incremental builder).

then when you ask for the number of infinite tetrahedra,
the search starts from one stored in the triangulation, say incident to A,
then by neighboring it finds all tetra incident to A and terminates
saying that there is 4 infinite tetrahdra.

If your triangulation is incorrect, you cannot expect to get right answers.

Try to run is_valid  on your triangulation.