[Gmsh] Remeshing with GMesh in 2D

[Dr. Stephan Schmidt]

Dear Prof. Geuzaine,

many thanks for the feedback! I have tried to use exactly the same procedure, but gmsh simply crashes without an error message when I try to e.g. refine the remeshed mesh.

Attached is a very minimal working example: „channel_orig.msh“ is the original mesh created by gmsh itself. It appears to be valid in all regards, my flow solver works flawlessly on this. „Remesh_channel.geo“ is the file I actually open for remeshing and I manage to remesh the geometry successfully.

But whenever I try to refine the rather coarse remeshed cannel using the gui, gmsh crashes without throwing any error messages and I am stuck on how to make a finer mesh. I am using the following build and version of gmsh:

Info    : -------------------------------------------------------
Info    : Gmsh version   : 2.11.0
Info    : Build OS       : MacOSX
Info    : Build options  : Ann Bamg Bfgs Blas(Custom) Blossom Chaco DIntegration Dlopen Fltk Gmm Jpeg(Fltk) Kbipack Lapack(Custom) MathEx Med Mesh Metis Mmg3d Mpeg NativeFileChooser Netgen ONELAB ONELABMetamodel OpenCascade OpenGL OptHom PETSc Parser Plugins Png(Fltk) Post SLEPc Salome Solver Tetgen(1.5) Voro3D Zlib
Info    : Build date     : 20151107
Info    : Build host     : Christophes-Mac.local
Info    : Packager       : geuzaine
Info    : Executable     : /Applications/Gmsh.app/Contents/MacOS/gmsh
Info    : Home directory : /Users/schmidt/
Info    : Launch date    : Fri Apr 29 17:47:49 2016
Info    : Command line   : /Applications/Gmsh.app/Contents/MacOS/gmsh
Info    : -------------------------------------------------------

I would be very thankful if you could kindly provide feedback with respect to this:

- How can I generate a finer mesh? Ideally, I would love to carry over the Delauney-weights associated with the original points into the remeshing information.
- Does the remeshed mesh also contain the same physical boundaries as the original mesh or do I have to re-identify the different boundaries afterwards manually? I know from the .stl 3D example how to do this when each physical boundary is contained within its own .stl file, but I would much appreciate hints on how to match a compound quantity with a physical surface and consequently a boundary marker in the case here, where everything stems from a single .msh file.

Regards and many thanks,
Stephan Schmidt



> Am 28.04.2016 um 21:53 schrieb Christophe Geuzaine <cgeuzaine at ulg.ac.be>:
> 
>> 
>> On 27 Apr 2016, at 01:49, Dr. Stephan Schmidt <stephan.schmidt at mathematik.uni-wuerzburg.de> wrote:
>> 
>> Dear all,
>> 
>> I am trying to use gmsh to remesh a 2D geometry.
>> 
>> So far, following the 3D examples (that is having a 2D stl surface as input to generate a 3D mesh) work fabulously just following the examples on compound surfaces, such as the one found here:
>> http://people.sc.fsu.edu/~jburkardt/examples/gmsh/t13.geo
>> 
>> But for my problem, I would need to remesh a 2D geometry (that is having a non-overlapping planar graph in a .msh file as input) seeking a 2D triangle mesh as output with reparameterized boundary graphs.
>> 
>> Is there any way of doing this as elegantly as the above link does for surfaces?
>> 
> 
> Sure, you can use the exact same procedure...
> 
> 
>> Regards and many thanks,
>> Stephan Schmidt
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> 
> -- 
> Prof. Christophe Geuzaine
> University of Liege, Electrical Engineering and Computer Science 
> http://www.montefiore.ulg.ac.be/~geuzaine <http://www.montefiore.ulg.ac.be/~geuzaine>
> 
> Tetrahedron V, July 4-5 2016: http://tetrahedron.montefiore.ulg.ac.be <http://tetrahedron.montefiore.ulg.ac.be/>
> Free software: http://gmsh.info <http://gmsh.info/> | http://getdp.info <http://getdp.info/> | http://onelab.info <http://onelab.info/>
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