[Gmsh] crash on 3D meshing (AW: Anisiotropic mesh in stacked layers)

[Christophe Geuzaine]

Hi Matthias,

There are two separate problems:

1) Currently MMG3D does not like having internal surfaces in the volume. Attached is a file with a single volume, which works ok.

@JF : have you tried MMG3D in such cases with internal surfaces?

2) "h2 / 100" pushes the initial tetrahedralization to the limit; h2/90 works fine over here.

All of this is still very experimental, though. It all needs to be tested and documented.

Thanks for the feedback!

Christophe

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On 11 Jul 2013, at 17:29, "Zenker, Dr. Matthias" <Matthias.Zenker at erbe-med.com> wrote:

> I forgot to say that the crash happens under Windows 7 with gmsh 2.8.0 64bit and with 2.7.1 32bit and 64bit.
>  
> Matthias
>  
> _____________________________________________
> Von: Zenker, Dr. Matthias 
> Gesendet: Donnerstag, 11. Juli 2013 16:57
> An: 'gmsh at geuz.org'
> Cc: 'Christophe Geuzaine [cgeuzaine at ulg.ac.be] (cgeuzaine at ulg.ac.be)'
> Betreff: crash on 3D meshing (AW: Anisiotropic mesh in stacked layers)
>  
>  
> Hi,
>  
> now that I have successfully created a anisotropic mesh width field for my geometry, I get a crash when I do the 3D meshing. 2D meshing works without problem. I have the impression that the desired mesh width may be too small. Is this so, and what is the smallest mesh width gmsh can cope with?
>  
> Thanks for an answer, this time?
>  
> Matthias
>  
> < Datei: layers.geo >>
> _____________________________________________
> Von: Zenker, Dr. Matthias 
> Gesendet: Donnerstag, 11. Juli 2013 16:41
> An: 'gmsh at geuz.org'
> Cc: 'Christophe Geuzaine [cgeuzaine at ulg.ac.be] (cgeuzaine at ulg.ac.be)'
> Betreff: AW: Anisiotropic mesh in stacked layers
>  
>  
> Hi again,
>  
> I have got it to work, but I still don?t understand why. It seems that the fields in MathEvalAniso have to be 1/(mesh_width)^2. But why?
> I have read the relevant part of the gmsh manual, but didn?t find the answer there.
> A short explanation and/or a pointer to more info would be highly appreciated.
>  
> Matthias
>  
> _____________________________________________
> Von: Zenker, Dr. Matthias 
> Gesendet: Mittwoch, 10. Juli 2013 17:09
> An: gmsh at geuz.org
> Cc: Christophe Geuzaine [cgeuzaine at ulg.ac.be] (cgeuzaine at ulg.ac.be)
> Betreff: Anisiotropic mesh in stacked layers
>  
>  
> Hi,
>  
> I want to mesh a geometry with layers stacked in z direction, where each layer should have a mesh width in the xy plane, and a different one in z direction. I have tried to combine the Box, Min and MathEval Aniso fields to achieve this (see attachment). But the mesh widths are not as I expect, in particular in layer 2 in z direction it should be 1/20 its height. What do I do wrong?
> How is the mesh width derived from the m11, m22 and m33 fields in MathEvalAniso?
>  
> Thanks for some explanations and hints,
>  
> Matthias
>  
> < Datei: layers.geo >>
>  
> 
> 
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> <layers.geo>

-- 
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science 
http://www.montefiore.ulg.ac.be/~geuzaine