CGAL users discussion list

["Laurent Rineau (GeometryFactory)" <>]

Le mardi 27 mars 2012 08:49:45 Zohar a écrit :
> I see, I look at the sources and the c3t3 facet iterator contains the
> triangulation iterator. I need to go over this material, thanks.
> 
> Here is my bug report:
> http://cgal-discuss.949826.n4.nabble.com/Bug-report-Mesh-generation-with-c2t
> 3-fails-td4509196.html
> 
> I'll to phrase my last question as a yes/no question:
> 
> 1. I have poly S.
> 2. I execute c2t3 remesher (polyhedron demo) on S, and produce poly P1.
> 3. I execute c3t3 mesh tet (mesh demo) and then convert to poly P2.
> 4. Concerning the surface, I use the same parameters for both algorithms.
> 
> Is P1 == P2 ?

No. Whatever parameters you have chosen for the steps 2 and 3 you described, 
the two algorithms do not guarantee to produce the same surface meshes.


The Surface Mesh Generator generates triangulated surface meshes embedded in 
3D Delaunay triangulations. Note that those surface meshes can be manifold of 
not, depending on the input surfaces, and chosen parameters.


The 3D Mesh Generator generates tetrahedral meshes embedded in 3D regular 
triangulations.

They are different implementations of a Delaunay triangulation refinement 
algorithm.

> Explanation: I'm trying to understand what's the difference between the two
> algorithms (they both rely on [BO05] reference), and what are the additional
> volume parameters in the mesh demo.

Please compare the two sections "Design and Implementation History" of their 
respective user manuals:

http://www.cgal.org/Manual/latest/doc_html/cgal_manual/Surface_mesher/Chapter_main.html#Section_47.7
http://www.cgal.org/Manual/latest/doc_html/cgal_manual/Mesh_3/Chapter_main.html#Section_50.1


The parameters used in the demo are described in the reference page for the 
CGAL::Mesh_criteria_3 class template:
http://www.cgal.org/Manual/latest/doc_html/cgal_manual/Mesh_3_ref/Class_Mesh_criteria_3.html

If you still have questions after reading those sections or pages, I can 
enter 
details, but for the moment I cannot tell you more.

-- 
Laurent Rineau, PhD
R&D Engineer at GeometryFactory           http://www.geometryfactory.com/
Release Manager of the CGAL Project       http://www.cgal.org/