CGAL users discussion list

["Sebastien Loriot (GeometryFactory)" <>]

Hello,

the polygon is actually invalid
(increase the check level to 3
        if (!poly.is_valid(false,3)) {
                std::cout << "poly is invalid\n";
        }
).

You have a dangling face with make the surface non-manifold.

One solution is to use this:

        if (!poly.is_valid(false,3)) {
              std::cout << "poly is invalid\n";
              stream.open("poly.off");
              nef_polyhedron nef;
              CGAL::OFF_to_nef_3 (stream, nef);
              std::cout << "created nef\n";
        }


Sebastien.


On 03/27/2013 09:28 PM, Cody Rose wrote:
> Hello,
>
> I receive an assertion failure when trying to convert the attached
> polyhedron to a nef polyhedron. The attached sample code demonstrates my
> problem. I am running this with CGAL 4.1, Boost 1.47, and LEDA 6.3. I am
> not sure if there is something about this polyhedron that causes the
> problem, but I could not find anything in the documentation to help me
> resolve this issue, and a cursory inspection of the .off doesn't show
> anything wrong to me (I'm probably just missing something simple).
>
> The example program out is as follows:
>
> loaded good poly with 16 vertices
> CGAL error: assertion violation!
> Expression : pe_prev->is_border() ||
> internal::Plane_constructor<Plane>::get_plane(pe_prev->facet(),pe_prev->facet()->plane()).
> has_on(pe_prev->opposite()->vertex()->point())
> File : c:\program files
> (x86)\cgal\include\cgal\nef_3\polyhedron_3_to_nef_3.h
> Line : 254
> Explanation:
> Refer to the bug-reporting instructions at
> http://www.cgal.org/bug_report.html
>
> Thank you,
> Cody Rose