CGAL users discussion list

["Laurent Rineau (GeometryFactory)" <>]

On Friday 30 October 2009 17:40:43 chris wrote:
> Hello,
> 
> I wonder if iterating over all finite facets of a Delaunay_triangulation_3
>  via Finite_facets_iterator should be same as iterating all of these facets
>  using something like:
> 
> Facet(c,i) for all finite cells and i in [0,1,2,3]
> 
> I noticed that the first approach, i.e. using Finite_facets_iterator, gives
> less facets and also gives facets whose cell is infinite.

In a 3D triangulation, all facets have to incident cells. To iterate over all 
finite facets, you need to choose which representation of the facet, among 
the 
two.

If you iterate over  all finite cells and i in [0,1,2,3], then Facet(c,i) 
will 
iterate twice on all finite facets, but facets on the convex hull, which be 
seen only once (because you do not iterate over infinite cells).

-- 
Laurent Rineau, PhD
R&D Engineer at GeometryFactory           http://www.geometryfactory.com/
Release Manager of the CGAL Project       http://www.cgal.org/