CGAL users discussion list

["Sebastien Loriot (GeometryFactory)" <>]

On 12/14/2013 11:26 AM, Zohar wrote:
> Hi,
>
> I have the mesh below, which I load with Polyhedron_3.exe demo. The
> non-manifold vertex is not detected. Also, when I constructed this mesh
> using Polyhedron_incremental_builder_3, the builder.test_facet() was
> successful.
Hopefully incremental builder does not complain because in this case the
non-manifoldness can be resolved by adding another triangle.


> Actually, I'm not even sure how can it detect that it's a bad
> facet, without knowing if I'll add facets that would remedy the situation.
>
> I suppose the answer is that the builder detects only non-manifold edges,
> although the Polyhedron_3 can't cope with non-manifold vertices (e.g.
> halfedge circulator around a vertex). Thus, I should use Nef.is_simple() to
> detect non-manifold. But nef requires a slow build and gmp. I was wondering
> if cgal offers a more efficient way (e.g. like MeshLab)?
Check the number of border edges incident to the vertex is more than 2.

Sebastien.

> Thanks,
> Zohar
>
>
> OFF
> 14 16 0
> -30.7325 -19.2431 -36.0255
> -30.8645 -17.8773 -35.3618
> -32.1125 -17.8012 -34.5874
> -31.1675 -17.2117 -34.713
> -31.808 -17.0522 -34.5372
> -31.1318 -17.4698 -34.6007
> -31.0541 -17.8668 -34.3054
> -31.0108 -17.0475 -34.2369
> -30.5593 -18.9909 -34.9694
> -30.6328 -17.7648 -34.7113
> -30.8158 -18.3803 -34.362
> -30.6815 -16.8104 -35.0021
> -30.9511 -17.0582 -34.4975
> -30.6251 -17.2115 -34.2052
> 3 5 9 12
> 3 0 8 9
> 3 11 3 12
> 3 1 5 3
> 3 0 9 1
> 3 5 2 4
> 3 1 9 5
> 3 5 6 2
> 3 11 12 13
> 3 7 6 5
> 3 9 10 13
> 3 5 12 7
> 3 8 10 9
> 3 7 12 3
> 3 9 13 12
> 3 5 4 3
>
>
>
>
> --
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> http://cgal-discuss.949826.n4.nabble.com/Undetected-non-manifold-vertex-in-poly3-tp4658551.html
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