CGAL users discussion list

[Stephane Tayeb <>]

 wrote:
> Hi,
> I'm using the function t.dual(Facet f). Following the documentation I
> expect as result segments or rays in the 3D case and a point if the
> dimension is 2. When considering a 2D complex embedded in a 3D
> triangulation (for example represented by C2T3) I obtain actually segment
> and rays for facets in the volume but I don't have points selecting facets
> on the surface.
> Can anyone help me to understand the observed behaviour?
> Thanks in advance!

Hi,

Am I wrong if I suppose that you use: c2t3.triangulation().dual(f), 
where f is a facet such as c2t3.is_in_complex(f) == true ?
In such a case, you are in the 3D case you described, as you are calling 
dual() on a 3D triangulation. Thus, the dual is a segment or a ray.

I think I can't help more since I don't know the behaviour you expect. 
Are you trying to retrieve the circumcenter of the surface triangles ? 
Do you expect something else, such as the center of the surface Delaunay 
ball of the facet (see Surface Mesher package documentation) ?

Best,

--
Stephane Tayeb
Software engineer - INRIA Sophia Antipolis
Geometrica Project-Team