[Gmsh] gmsh Digest, Vol 97, Issue 20

[Paavo Mäkelä]

Hi,

I was thinking about removing the 3rd coordinate definition completely from
the msh file via some script, but being a bit of newbie in linux scripting
languages.. is there an existing script somewhere?


-PM


Hi,
>
> I have had the same problem. For me, the solution was to make sure that the
> 3rd coordinate is really exactly equal (e.g. to zero) for all points. If it
> isn't, Elmer will detect a 3D geometry.
>
> HTH,
>
> Matthias
>
> -----Urspr?ngliche Nachricht-----
> Von: Geordie McBain [mailto:gdmcbain at freeshell.org]
> Gesendet: Montag, 21. Februar 2011 00:37
> An: Paavo M?kel?
> Cc: gmsh at geuz.org
> Betreff: Re: [Gmsh] 2D mesh generation problem
>
> 2011/2/21 Paavo M?kel? <pamakela at gmail.com>:
> > Hi,
> >
> > I have had a working workflow for making 2D meshes from trimmed NURBS
> > geometry made in Aliasstudio. I use the Elmer solver to perform flow
> > simulations.
> >
> > I recently continued my work on my personal design project and noticed
> > that GMSH will produce meshes that contain 3 dimensional elements (as
> > per Elmer software's log) and sometimes Elmer software detects 3
> > dimensional mesh, even though the original geometry is/was a 2D plane!
> > What am I doing wrong here? Loading the original IGES file straight
> > into Elmer software results in 2D mesh with 2D elements which implies
> > the exported cad file is Ok (but because elmer can't handle trimmed 2d
> > NURBS planes, I must always go through Gmsh). I think only 2D elements
> > should be generated if you only use the 2D meshing functionality in
> > Gmsh? I can post my IGES file if there is need for that.
>
> Hello, I haven't tried Elmer (yet), but I believe Gmsh only outputs
> three-dimensional meshes, even if your geometry is two-dimensional or even
> one-dimensional; i.e. the nodes always have three coordinates.
>
> Which output format do you use?  For FreeFem++, for two-dimensional
> problems, I output in MEDIT .mesh from Gmsh, but then modify it in AWK to
> cull the z-coordinates.  Perhaps a workaround like that would be reasonable?
>
>
>
>
>
>
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