CGAL users discussion list

["Rubén Martínez" <>]

I find the solution, you need read the polyedron in one variable P for
example, and finally, when you need write the content of the
Nef_polyedhra, use the convert to polyedron with other polyedra
variable Q, for example, and then it run correctly, here the new code:

int main() {

  Polyhedron P, Q;
  char *path;
  path = "polyhedron.off";

  Q = readOFF (path);

  if(Q.is_closed()) {
    Nef_polyhedron N1(Q);

    if(N1.is_simple()) {
          N1.convert_to_Polyhedron(P);
      std::cout << P;
          std::cout << "Número de Vértices: ";
          std::cout <<  P.size_of_vertices ();
    }
    else
      std::cerr << "N1 is not a 2-manifold." << std::endl;
  }
}

Thanks for the help, this is the solution.

Bye

On 8/4/07, Rubén Martínez 
<>
 wrote:
> The complete code is this:
>
> #include <CGAL/Gmpz.h>
> #include <CGAL/Homogeneous.h>
> #include <CGAL/Polyhedron_3.h>
> #include <CGAL/IO/Polyhedron_iostream.h>
> #include <CGAL/Nef_polyhedron_3.h>
> #include <CGAL/IO/Nef_polyhedron_iostream_3.h>
> #include <iostream>
> #include <fstream>
>
> typedef CGAL::Homogeneous<CGAL::Gmpz>  Kernel;
> typedef CGAL::Polyhedron_3<Kernel>  Polyhedron;
> typedef CGAL::Nef_polyhedron_3<Kernel> Nef_polyhedron;
> typedef Kernel::Vector_3  Vector_3;
> typedef Kernel::Aff_transformation_3  Aff_transformation_3;
>
> using namespace std;
>
> Polyhedron readOFF(char *p)
> {
>       Polyhedron P;
>       ifstream file;
>       file.open(p);
>
>       file >> P;
>
>       return P;
> }
>
> int main() {
>
>   Polyhedron P;
>   char *path;
>   path = "polyhedron.off";
>
>   P = readOFF (path);
>
>   if(P.is_closed()) {
>     Nef_polyhedron N1(P);
>
>     if(N1.is_simple()) {
>         N1.convert_to_Polyhedron(P);
>       std::cout << P;
>         std::cout << "Número de Vértices: ";
>         std::cout <<  P.size_of_vertices ();
>     }
>     else
>       std::cerr << "N1 is not a 2-manifold." << std::endl;
>   }
> }
>
> Is a copy of a one example of basic CGAL, with some changes, but I dot
> know because I have this problem...
>
> On 8/3/07, Peter Hachenberger 
> <>
>  wrote:
> > Hi Ruben,
> >
> > I've never seen that happen before. CAn you please send me the whole
> > code, i.e., with type definitions. As far as I can see, this part of the
> > code is fine.
> >
> > Peter
> >
> > On Fri, 2007-08-03 at 12:49 +0200, Rubén Martínez wrote:
> > > My problem reside in de transformation from Nef 3 to Polyedron, this
> code:
> > >
> > > N1.convert_to_Polyhedron(P);
> > >
> > >
> > > My complete code is this:
> > >
> > > main(){
> > >
> > > Polyhedron P;
> > >   char *path;
> > >   path = "polyhedron.off";
> > >
> > >   P = readOFF (path);
> > >
> > >   if(P.is_closed()) {
> > >     Nef_polyhedron N1(P);
> > >
> > >     if(N1.is_simple()) {
> > >     N1.convert_to_Polyhedron(P);
> > >       std::cout << P;
> > >     std::cout << "Número de Vértices: ";
> > >     std::cout <<  P.size_of_vertices ();
> > >     }
> > >     else
> > >       std::cerr << "N1 is not a 2-manifold." << std::endl;
> > >   }
> > > }
> > >
> > > And when I convert N1 (Nef 3) to P (Polyedron) i observe that the
> > > vertex are duplicated, for example:
> > >
> > > In this tetrahedron, i f I load this in the Nef 3, i have this:
> > >
> > > OFF
> > > 8 6 0
> > > # vertices
> > >  -1 -1  1
> > >  -1  1  1
> > >   1  1  1
> > >   1 -1  1
> > >  -1 -1 -1
> > >  -1  1 -1
> > >   1  1 -1
> > >   1 -1 -1
> > > # facets
> > >   4  3 2 1 0
> > >   4  0 1 5 4
> > >   4  6 5 1 2
> > >   4  3 7 6 2
> > >   4  4 7 3 0
> > >   4  4 5 6 7
> > >
> > >
> > > but if I execute the code N1.convert_to_Polyhedron(P); i obtain this
> > result
> > > OFF
> > > 16 12 0
> > >
> > >  -1 -1  1
> > >  -1  1  1
> > >   1  1  1
> > >   1 -1  1
> > >  -1 -1 -1
> > >  -1  1 -1
> > >   1  1 -1
> > >   1 -1 -1
> > >  -1 -1  1
> > >  -1  1  1
> > >   1  1  1
> > >   1 -1  1
> > >  -1 -1 -1
> > >  -1  1 -1
> > >   1  1 -1
> > >   1 -1 -1
> > >
> > >   4  3 2 1 0
> > >   4  0 1 5 4
> > >   4  6 5 1 2
> > >   4  3 7 6 2
> > >   4  4 7 3 0
> > >   4  4 5 6 7
> > >   4  12 15  11 8
> > >   4  12  8  9 13
> > >   4  8  11  10  9
> > >   4  12  13  14  15
> > >   4  15  14  10  11
> > >   4  13  9  10  14
> > >
> > > Anyone know any solution for this problem?????
> > >
> > > Thanks
> > >
> > > RMG
> > >
> >
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