CGAL users discussion list

["Max" <>]

Hi

From the doc, I get the brief definitions of them:

interior():With interior() one deselects all boundary items.
closure():with closure() one selects all boundary items.
boundary():with boundary() one deselects all volumes.

To verify my understanding of them, I wrote the following 
code to test:

#include <CGAL/Gmpz.h>
#include <CGAL/Extended_homogeneous.h>
#include <CGAL/Nef_polyhedron_3.h>

typedef CGAL::Extended_homogeneous<CGAL::Gmpz>  Kernel;
typedef CGAL::Nef_polyhedron_3<Kernel>  Nef_polyhedron;
typedef Kernel::Plane_3  Plane_3;

int main() {
        Nef_polyhedron N_1(Plane_3( 1, 0, 0,-1), Nef_polyhedron::INCLUDED);
        Nef_polyhedron N_2(Plane_3( 1, 0, 0,-1), Nef_polyhedron::EXCLUDED);
        Nef_polyhedron N_pl = N_1 - N_2;                // a plane slice
        Nef_polyhedron N_empty(Nef_polyhedron::EMPTY);

        CGAL_assertion(N_1.interior() == N_2);
        CGAL_assertion(N_2.interior() == N_2);
        CGAL_assertion(N_1.closure() == N_pl);
        CGAL_assertion(N_2.closure() == N_pl);
        CGAL_assertion(N_1.boundary() == N_pl);
        CGAL_assertion(N_2.boundary() == N_empty);
}

It's really a surprise for me to get ALL OF THE ASSERTIONS FAILED!
If it should be the correct behavior, my understanding is COMPLETELY
wrong.

Could anybody help me with understanding these methods?

Thanks.

Max