CGAL users discussion list

["Sebastien Loriot (GeometryFactory)" <>]

Adding this:

assert(model.is_pure_triangle());
Polyhedron_3::Face_iterator fit=model.facets_begin();
for (fit!=model.facets_end();++fit){
   if (fit->halfedge()->is_border()) continue;
  kernal::Plane_3 plane(fit->halfedge()->vertex()->point(),
                        fit->halfedge()->next()->vertex()->point(),
                        fit->halfedge()->opposite()->vertex()->point()
  );
  assert(!plane.is_degenerate());
}

after this:
file>>model;

you will see that your input polyhedron is not a valid input for a 
Nef_polyhedron_3: at least one facet
is degenerate, it is made of 3 collinear points.

S.

johnzjq wrote:
> Dear Sebastien,
>
> Here attached a problematic model.
> http://cgal-discuss.949826.n4.nabble.com/file/n3335356/223.off 223.off 
>
> The minimal example is as following:
> http://cgal-discuss.949826.n4.nabble.com/file/n3335356/example.cpp
> example.cpp 
>
> I got an assertion like this:
> Error !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
> CGAL error: assertion violation!
> Expression : pe_prev->is_border() ||
> !pe_prev->facet()->plane().is_degenerate()
> File          : c:\program files
> (x86)\cgal-3.7\include\cgal\nef_3\polyhedron_3_to_
> nef_3.h
> Line         : 261
> Explanation:
> Refer to the bug-reporting instructions at
> http://www.cgal.org/bug_report.html
>
> Thanks for your kindly help.
>
> John
>
> --
> View this message in context: 
> http://cgal-discuss.949826.n4.nabble.com/Assertion-violation-when-converting-polyhedron-to-Nef-polyhedron-tp3220004p3335356.html
> Sent from the cgal-discuss mailing list archive at Nabble.com.