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["Max" <>]

I happened to find the Nef_polyhedron_3::Build_polyhedron<HDS> template class,
it's quite similar to my code, except that it uses the visitor pattern.

I guess there is an exsting class or function that can meet my need.

Max
>Hi all,
>
>I want to integrate several Off models(manifold) into a single model.
>I found the incremental builder example for polyhedron in the documentation.
>
>I adapted the code for my purpose. Everything seems to be smooth. The 
>program 
>ends successfully, and the visulization of the result is just want I 
>expected.
>
>However, having a closer look at the resulting file, I find a strange 
>phenomenom - the resulting number of vertices and facets is much greater 
>than what they 'should me'.
>
>For example, I was combining 6 similar but disconnected models, each has 578 
>vertices and 1152 facets. To my surprise, the resulting model has 12138 
>vertices
>and 24192 facets, far more than 6*578 and 6*1152, respectively.
>
>All of the working code is as follows:
>
>// A modifier creating a polyhedron with the incremental builder
>template <class Polyhedron_3>
>class Build_polyhedron : public CGAL::Modifier_base<typename 
>Polyhedron_3::HDS> 
>{
>       typedef typename Polyhedron_3::HDS HDS;
>       typedef typename Polyhedron_3::Point_const_iterator Point_iterator;
>       typedef typename Polyhedron_3::Facet_const_iterator Facet_iterator;
>       typedef typename Polyhedron_3::Halfedge_around_facet_const_circulator 
> Halfedge_facet_circulator;
>
>       const Polyhedron_3 &p_;
>       Build_polyhedron() {}           // not open to user
>
>public:
>       explicit Build_polyhedron(const Polyhedron_3 &p) : p_(p) {}
>
>       void operator() (HDS& hds) 
>       {
>               typedef CGAL::Polyhedron_incremental_builder_3<HDS> Builder;
>
>               // Postcondition: `hds' is a valid polyhedral surface.
>               Builder B(hds, true);
>
>               // building a surface
>               B.begin_surface(p_.size_of_vertices(), 1);
>
>               // building vertices
>               for(Point_iterator p = p_.points_begin(); p != 
> p_.points_end(); ++p)
>                       B.add_vertex(*p);
>
>               // building facets
>               for(Facet_iterator f = p_.facets_begin(); f != 
> p_.facets_end(); ++f) 
>               {
>                       B.begin_facet();
>
>                       Halfedge_facet_circulator c = f->facet_begin();
>                       // Facets in polyhedral surfaces are at least 
> triangles.
>                       CGAL_assertion(CGAL::circulator_size(c) >= 3);
>       
>                       do {
>                               
> B.add_vertex_to_facet(std::distance(p_.vertices_begin(), c->vertex()));
>                       } while ( ++c != f->facet_begin());
>
>                       B.end_facet();
>               }
>
>               B.end_surface();
>       }
>};
>
>// Integrate source into target
>template<class Polyhedron_3>
>void IntegratePolyhedron(Polyhedron_3 &target, const Polyhedron_3 &source)
>{
>       Build_polyhedron<Polyhedron_3> polyhedron(source);
>       target.delegate(polyhedron);
>}
>
>Thanks in advance for any help.
>
>B/Rgds
>Max
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