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["Sebastien Loriot (GeometryFactory)" <>]

Since you are using Nef, what about computing the union of the two
spheres and then extract the boundary?

N1+=N2;
Polyhedron result;
N1.convert_to_polyhedron(result);

see:
http://www.cgal.org/Manual/latest/doc_html/cgal_manual/Nef_3_ref/Class_Nef_polyhedron_3.html

Sebastien.


On 04/01/2012 04:13 PM, Oleg wrote:
> Hi all!
>
> Newbie question. I have two triangulated intersecting spheres (3D
> polyhedrons) and want to exclude the triangles from each sphere surface that
> are inside the other sphere. What would be the easiest way to do that? Here
> is what I'm trying and so far it doesn't work (skipping the unnecessary
> code):
>
> #include<CGAL/Exact_predicates_exact_constructions_kernel.h>
> #include<CGAL/Polyhedron_3.h>
> #include<CGAL/Nef_polyhedron_3.h>
>
> typedef CGAL::Exact_predicates_exact_constructions_kernel  Kernel;
> typedef Kernel::Triangle_3 Triangle;
> typedef CGAL::Polyhedron_3<Kernel>  Polyhedron;
> typedef Polyhedron::Facet_const_iterator Facet_const_iterator;
> typedef Nef_polyhedron::Volume_const_handle     Volume_const_handle;
>
> std::vector<Triangle>  triangles;
>
> //The spheres are represented by two 3D polyhedrons:
>
> Polyhedron P1;
> Polyhedron P2;
> Volume_const_handle v;
>
> //I convert each polyhedron to a nef_polyhedron:
>
> Nef_polyhedron N1(P1);
> Nef_polyhedron N2(P2);
>
> //and check if a vertex from P1 belongs to N2:
>
> for ( Facet_const_iterator i = P1.facets_begin(); i != P1.facets_end();
> ++i){
>    if (!assign(v, N2.locate(i->halfedge()->vertex()->point()))&&
>        !assign(v, N2.locate(i->halfedge()->next()->vertex()->point()))&&
>        !assign(v,
> N2.locate(i->halfedge()->next()->next()->vertex()->point()))) {
>         Triangle t(i->halfedge()->vertex()->point(),
>                    i->halfedge()->next()->vertex()->point(),
>                     i->halfedge()->next()->next()->vertex()->point());
>          triangles.push_back(t);
>         }
>      }
> //Same for P2
>
> The goal is to have vector 'triangles' with those triangles from each
> surface that are not inside the other sphere. So far it compiles, but I get
> empy vector in the output. What do I miss here? Or is there an easier way to
> achieve the same goal? Thanks for any help.
>
>
> --
> View this message in context: 
> http://cgal-discuss.949826.n4.nabble.com/Determining-if-a-point-is-inside-a-polyhedron-tp4523460p4523460.html
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