[Gmsh] GMSH 3D mesh generation fails

[Zenker, Dr. Matthias]

Hi Ivan,

as pointed out by Mikhail yesterday (look at the fixed geo file in his mail, see attachment), the problem comes from duplicated lines. Your surfaces don't overlap, but the lines do. gmsh will generate different 1D meshes on the lines resulting in a nonconformal 2D mesh (i.e. nodes are not identical on identical lines) which will be detected as overlapping when gmsh tries to make a 3D mesh. So the solution is to have unique lines without overlaps between the surfaces. AFAIK gmsh cannot resolve and heal those overlaps automagically.

HTH,

Matthias

> -----Ursprüngliche Nachricht-----
> Von: xsimecek at fit.cvut.cz [mailto:xsimecek at fit.cvut.cz]
> Gesendet: Mittwoch, 26. Juni 2013 08:48
> An: gmsh at geuz.org
> Betreff: [Gmsh] GMSH 3D mesh generation fails
>
> Dear GMSH developer(s),
>
> I did some experiments to avoid "self intersecting surfaces" error message
>
> I used very simple objects(one rectangular cuboid minus another rectangular
> cuboid = "hole in the box")
> 2 examples are attached.
>
> I find out that "self intersecting surfaces" error message disappears when I
> decrease the fourth parameter in point definition, but problem with
> generation of 3D mesh remains:
>
> I try all 3D generators:
> Dealunay - stop responding, after few minutes does not give any result
> Frontal - surface mesh not consistent error messsage Fr. Dealunay - works
> but the mesh is incorrect Fr. Hex - works but the mesh is incorrect MMG3D -
> kills the process gmsh !
> R-tree - stop responding,after few minutes does not give any result
>
> So, either I don't get any result or the result is incorrect (generated mesh is
> across the "hole")
>
> What do I wrong?
>
> I have used GMSH 2.7.1:
> FLTK 1.3.1
> Win OS, build date 20130512
>
> Thanks for any help,
>
> Ivan Simecek


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