CGAL users discussion list

["Sebastien Loriot (GeometryFactory)" <>]

Dear Noel,

could you please provide a complete compilable example showing the problem?

Thanks,

Sebastien.

On 03/07/2013 01:13 PM, Noel Warren wrote:
> I have a function that splits Nefs into smaller nefs from the shells of
> the volumes.  I am doing it using an undocumented Nef constructor.  In
> the majority of cases it works a charm but ocasionally it fails.  I have
> attatched a nef that fails (infact it only has one volume so should
> return an Array of length 1 containing a Nef) when trying to split.
>
> Here is a code snippet
>
> vector<Nef_polyhedron_3> nefs;
> Nef_polyhedron_3::Volume_const_iterator vi = ++N.volumes_begin();
> Nef_polyhedron_3::Shell_entry_const_iterator si;
> CGAL_forall_volumes(vi,N) {
> if(vi->mark()) {
> Nef_polyhedron_3::Shell_entry_const_iterator si;
> CGAL_forall_shells_of(si, vi) {
> Nef_polyhedron_3::SFace_const_handle sfch(si);
> Nef_polyhedron_3 O(N,sfch);
> nefs.push_back(O);
> }
> }
> }
>
> Here is the error...
>
> CGAL ERROR: assertion violation! (RuntimeError)
> Expr: itl != it->second.end()
> File: /usr/local/include/CGAL/Nef_3/SNC_external_structure.h
> Line: 1102
>
> If I shouldn't be using this Nef constructor, how should I go about
> "splitting" a nef into smaller ones.  Thanks in advance for your time.