CGAL users discussion list

[Zohar <>]

1.
http://cgal-discuss.949826.n4.nabble.com/Contibution-for-CGAL-Complex-3-in-triangulation-3-polyhedron-builder-h-td2307832.html

2.
A. It converts tets from CGAL to tets for vtk, I'm not sure how it could
help me.
B. But there is the
MeshComplex_3InTriangulation_3::Facets_in_complex_iterator(), which gives
the surface facets. I can't see a link (?) to what the facet consists of,
but I assume there's a begin_vertices(), or I can look in the source for
that. 
C. I could hold in an std::map the vertex handles to some arbitrary ids, so
I could connect between common vertices of the facets. 
D. I can use c3t3.surface_patch_index(Facet f), to retrieve the connected
component the facet belongs to - if that's what I think it is, and here
things get a bit murky. I'm not fully sure about the definitions, or what's
going on here, and that's why I implied that a depiction might help. There
are two related links in the manual:

http://www.cgal.org/Manual/latest/doc_html/cgal_manual/Mesh_3/Chapter_main.html
http://www.cgal.org/Manual/latest/doc_html/cgal_manual/Mesh_3_ref/Concept_MeshComplex_3InTriangulation_3.html

On the second link, second paragraph:

"To distinguish the faces of the embedded 3D complex from the faces of the
triangulation, we call the faces of the embedded complex respectively
subdomains, for 3D faces and surface patches, for 2D faces, while the
triangulations faces are called respectively cells, facets, edges and
vertices."

I'm not sure if it's bad punctuation, but there's a problem in this sentence
and it doesn't make sense to me.

Please help me understand the c3t3 structure. It's a 3 simplicial complex,
which is embedded as a triangulation. The simplicial complex is partitioned
to a few spaces (sub-domains?), each space is composed of tets, and its
boundary surface is composed of facets. Referring to the first link, figure
50.1, I assume that each colored set of tets is an independent space.
Are there facets only on the surface, since a tet is also made of 4 facets?
Why do we need to distinguish between the simplicial complex and its
embedding - the triangulation?
When I extract a polyhedron, I want only facets that touch 'air', and not
the ones between the spaces, how do I know if a facet touches air?
When I reconstruct a c3t3 from a poly, how many spaces will I have?

3.
I thought it was buggy officially. Anyway here is one of the standard
models, try to remesh it with poly_3 demo:

http://svn.code.sf.net/p/mymayaplugins/code-0/trunk/tmp/camel.off

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