CGAL users discussion list

[Matthias Teich <>]

Hi!

My first guess would be that your input mesh contains multiple vertices, 
e.g that your cube mesh has not only 8 vertices.
I used a very similar code to transform my Mesh to CGAL.



Icek schrieb:
> Hello, Im trying to construct Polyhedron from my mesh structure. And then
> NefPolyhedron from polyhedron. I found that I have to use Incremental
> builder, but resulting polyhedron is_closed() is always false, even when my
> mesh is simple cube. And NefPolyheron requires closed polyhedron, so is this
> piece of code right? Or how do I create polyhedron from points? 
>
> template <class HDS> class PolyhedronFromMesh : public
> CGAL::Modifier_base<HDS> 
> {
> public:
>     PolyhedronFromMesh(const Mesh & mesh) : _mesh(mesh)
>     {
>
>     }
>
>     void operator()( HDS& hds)
>     {
>         // Postcondition: `hds' is a valid polyhedral surface.
>         CGAL::Polyhedron_incremental_builder_3<HDS> B( hds, false);
>
>         typedef typename HDS::Vertex   Vertex;
>         typedef typename Vertex::Point Point;
>
>         unsigned int nPoints = _mesh.Points.size();
>         unsigned int nFacets =  _mesh.Indices.size() ? _mesh.Indices.size()
> / 3 : nPoints / 3;
>
>         B.begin_surface(nPoints,nFacets);
>
>         for(unsigned int i = 0; i < nPoints; i++)
>         {
>             Vec3 p = _mesh.Points[i];           
>             B.add_vertex(Point(p.x,p.y, p.z));
>         }
>
>         if(_mesh.Indices.size())
>             for(unsigned int i=0; i < _mesh.Indices.size(); i+=3)
>             {
>             B.begin_facet();
>             B.add_vertex_to_facet((long unsigned int)_mesh.Indices[i]);
>             B.add_vertex_to_facet((long unsigned int)_mesh.Indices[i+1]);
>             B.add_vertex_to_facet((long unsigned int)_mesh.Indices[i+2]);
>             B.end_facet();
>         }
>         else
>             for(unsigned int i=0; i < _mesh.Indices.size(); i+=3)
>             {
>             B.begin_facet();
>             B.add_vertex_to_facet( i);
>             B.add_vertex_to_facet( i+1);
>             B.add_vertex_to_facet( i+2);
>             B.end_facet();
>         }
>
>         B.end_surface();
>     }
>
>     const Mesh & _mesh;
> };
>
>   
> ------------------------------------------------------------------------
>
>
> Eingehende eMail ist virenfrei.
> Von AVG uberpruft - www.avg.de 
> Version: 8.5.375 / Virendatenbank: 270.13.31/2265 - Ausgabedatum: 07/26/09 17:59:00 
>
>