CGAL users discussion list

[Peter Hachenberger <>]

I guess the constructor Nef_polyhedron_3 (II v_first, II v_last)
does something totally different than you expect. This constructor
creates a Nef_polyhedron_3 that is a polygon. If you want to create a
Nef_polyhedron_3 from a point cloud, you can construct a convex
Polyhedron_3 via convex_hull_3 and convert it to a Nef_polyhedron_3.

Peter

On Wed, 2007-08-29 at 08:12 +0200, Zorglub78 wrote:
> Hi all,
> 
> When I try to use this very trivial code:
> 
> #include <CGAL/basic.h>
> #include <CGAL/Gmpq.h>
> #include <CGAL/Homogeneous.h>
> #include <CGAL/Nef_polyhedron_3.h>
> 
> typedef CGAL::Gmpz NT;
> typedef CGAL::Homogeneous<NT> Kernel3D;
> typedef Kernel3D::Point_3                                      Point3D;
> typedef CGAL::Iso_cuboid_3<Kernel3D>                           Cuboid3D;
> typedef CGAL::Nef_polyhedron_3<Kernel3D>                       Polyhedron3D;
> 
> using std::vector;
> 
> int main(int argc, char** argv)
> {
>  
>   Cuboid3D c1(Point3D(0,0,0), Point3D(3,3,3));
>   vector<Point3D> vp;
>   for(u_int i=0; i<8; ++i)
>     vp.push_back(c1[i]);
>  
>   Polyhedron3D p(vp.begin(), vp.end(), true);
> }
> 
> Execution fails with the following error:
> "Conversion from vertex cycle to Nef_polyhedron_3 was not successful. 
> Error history: Direction of projection is 'z'. -> Different vertices are 
> projected to same location! Now, direction of projection is 'x'. -> 
> Different vertices are projected to same location! Now, direction of 
> projection is 'y'. -> Different vertices are projected to same location! 
> Finally, empty Nef_polyhedron_3 was constructed."
> 
> Am I doing wrong something, or is there a bug in Nef_polyhedron_3 (II 
> v_first, II v_last) ?
> 
> Thanks for responses.
> 
>