CGAL users discussion list

["Sebastien Loriot (GeometryFactory)" <>]

Looks like something is weird indeed. I suspect the nef to be invalid
(even if the is_valid says the converse). Do you have the two
nefs used to produced it, together with the operation type?

Sebastien.


On 03/11/2013 06:32 PM, Noel Warren wrote:
> Hi Sebastien
>
> I actually use CGAL wrapped in ruby.  You can checkout my repo at
> (https://github.com/noelwarr/rgal).  Let me know if you want any
> licenses put anywhere.  (I do know about the cgal-bindings project but I
> couldn't get my head around swig.)
>
> Because it is a pain to compile the whole RGAL repo I have put together
> a little cpp file and nef file that fails to create a nef from one of
> the volumes.  The interesting thing is that even though the same volume
> fails, it throws a different error.  The cpp file complains about a
> segmentation fault whereas my ruby wrapped code produces...
>
> CGAL ERROR: assertion violation! (RuntimeError)
> Expr: cet->get_index() == ce->twin()->get_index()
> File: /usr/local/include/CGAL/Nef_3/SNC_external_structure.h
> Line: 1169
>
> Even wierder is the fact that if I don't regularize the nef, the cpp
> code produces a result but my ruby code continues to fail.
>
> Let me know if you need something else.
>
> 2013/3/11 Sebastien Loriot (GeometryFactory) 
> <
> <mailto:>>
>
>     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.
>
>
>
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