CGAL users discussion list

[Omer Ozturk <>]

Hello everyone,
I'm having problem with building a polyhedron from points. What i'm doing is
like the following;

1. Create a sphere from implicit function:

 Tr tr;            // 3D-Delaunay triangulation
  C2t3 c2t3 (tr);   // 2D-complex in 3D-Delaunay triangulation
  // defining the surface
  Surface_3 surface(sphere_function,             // pointer to function
                    Sphere_3(CGAL::ORIGIN, 2.)); // bounding sphere
  // Note that "2." above is the *squared* radius of the bounding sphere!
  // defining meshing criteria
  CGAL::Surface_mesh_default_criteria_3
 criteria(30.,  // angular bound
                                                     0.1,  // radius bound
                                                     0.1); // distance bound
  // meshing surface
  CGAL::make_surface_mesh(c2t3, surface, criteria,
CGAL::Non_manifold_tag());

2. Insert the mesh points into a list:

Tr::Point_iterator iterator;

  for(iterator = tr.points_begin(); iterator != tr.points_end();
iterator++){

          Point p(iterator->x(), iterator->y(), iterator->z());
          points.append(p);
          
  }
3. Build the polyhedron from these points:

template <class HDS>
class Build_triangle : public CGAL::Modifier_base<HDS> {
        
public:
        QList<Point> pts;

        void setPoints(QList<Point> prmt){
                pts = prmt;
        }

        Build_triangle() {}
    void operator()( HDS& hds) {
        // Postcondition: hds is a valid polyhedral surface.
        CGAL::Polyhedron_incremental_builder_3<HDS> B( hds, true);
                B.begin_surface(pts.length(), pts.length()/3, 0);
        typedef typename HDS::Vertex   Vertex;
        typedef typename Vertex::Point Point;
                for(int i=0;i<pts.length(); i++){
                        B.add_vertex( Point( pts[i].x, pts[i].y, pts[i].z));
                }
        B.begin_facet();
                for(int i=0;i&lt;pts.length(); i++){
        B.add_vertex_to_facet( i);
                }
        B.end_facet();
        B.end_surface();
    }
};

//Some code here...

   Polyhedron P;
        Build_triangle&lt;HalfedgeDS> triangle;
        triangle.setPoints(points);
   P.delegate( triangle);

But when i do that, i get a line instead of a sphere. What am i doing wrong? 

Thanks.



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