CGAL users discussion list

["Sebastien Loriot (GeometryFactory)" <>]

If you use Polyhedron, the off must be a valid manifold surface.
If not you can use the function OFF_to_nef_3 from
include/CGAL/OFF_to_nef_3.h

Sebastien.

On 12/22/2015 12:12 PM, SHYAM SUNDAR KANNAN wrote:
> Hello Everyone,
>
> I am trying to find the symmetric difference of two polyhedrons. In
> order to perform this Boolean operation in 3D I want to convert my
> Polyderon_3 to Nef_Polyhedron_3.
>
> I constructed my polyhedron with data from an .OFF file. Later when I
> try to convert the Polyhedron_3 to Nef_Polyhedron_3 as
>
> std::ifstream stream(path/data.off");
>      if(!stream) {
>          std::cerr << "Cannot open the reconstructed.off file!\n";
>          return 1;
>      }
>      Polyhedron R;
>      stream >> R;
>      if(!stream) {
>          std::cerr << "reconstructed.off is not a polyhedron\n";
>          return 1;
>      }
>
>      Nef_polyhedron N(R);  //getting error in this line
>
>
> (I am using Extended_homogeneous Kernel)
>
> the conversion fails in most of the cases. It works for simple 3D
> objects like cube etc.
>
> For example:
> It works for a cube with rectangular hole but fails for a cube with a
> cylindrical hole.
>
> Can anyone explain the reason for this. Are there any constraints
> causing this limitation.
>
> Is there way to convert all Polyhedrons to Nef_Polyherdon?
>
>
> Thanking You in advance,
>
>
> Regards,
> Shyam Sundar Kannan.