CGAL users discussion list

[Monique Teillaud <>]

Emerson Carride wrote:
> How can i know if a given edge from a delaunay triangulation is in the 
> board?

I guess you mean boundary, or more precisely convex hull, am I right?

A CGAL triangulation has no boundary since the infinite region outside 
the convex hull is triangulated, using an additional vertex at infinity 
(see the user manual, this is explained).

If you want to know whether an edge belongs to the convex hull, you can
- if you are in 2d: look at the two facets incident to it and check 
whether one of this facets is infinite,
- if you are in 3d: look at the incident cells (there is a circulator 
for this) and check whether one of them is infinite.

To know more, look at the manual, there is a typedef defining an edge. 
Also, there were several thread about this on this list recently.

> Emerson Amade Carride
> Matemática Aplicada e Computação Científica
> Instituto de Ciências Matemáticas e Computação
> USP - São Carlos
> tel: (16) 3411 0877; (11) 4538 3315 ; cel: (11) 71289888

Thank you for this introduction.
I wish more users writing from a gmail address were introducing 
themselves in a similar way.

best,
        Monique Teillaud