[Gmsh] freefemm++
Dimitrios Eftaxiopoulos
eftaxiop at central.ntua.gr
Thu Jun 25 12:20:32 CEST 2009
I recently managed to import a .mesh file to freefem++. The mesh was created in
gmsh and was exported to the .mesh format within gmsh. No particular
intervention was needed.
Regards
Dimitris
Στις Πέμπτη 25 Ιούνιος 2009 07:00:53 Geordie McBain γράψατε:
> On Sat, Jun 7, 2008 at 1:05 AM, David Colignon<David.Colignon at ulg.ac.be>
wrote:
> > Hi,
> >
> > if freefem++ can read the medit mesh format, then the latest Gmsh version
> > 2.2 is able to export a mesh in this medit format.
>
> Yes, but I found I had to reorder the listing of vertices for each
> tetrahedron in the output MEDIT .mesh file or FreeFem++ (v. 3.3-3)
> thinks the volumes are negative (and other finite element operations
> nonsensical). I did this in Gawk (an action like { print $1, $3, $2,
> $4, $5 } on the lines following the one matching "Tetrahedra"). Did
> others have this problem?
> Should the writeMESH function be modified? I think it'd be only a
> couple of local lines of code, which I could supply. I couldn't see a
> specification for the convention on vertex-numbering in the MEDIT
> .mesh format (Frey's INRIA technical report
> http://www.ann.jussieu.fr/~frey/publications/RT-0253.pdf). Is it only
> FreeFem++'s
> interpretation of the MEDIT .mesh format that is idiosyncratic?
> I think there are only two essentially different ways to number the
> four vertices in a tetrahedron, just as there are only two for a
> three-node triangle in a plane. For the triangle, it's clockwise or
> counterclockwise looking down on the plane, and for the tetrahedron
> similarly for the triangle defined by the first three vertices,
> looking from the fourth vertex. The Gmsh .msh file format description
> in Gmsh ch. 9 does seem to imply one of these two choices rather than
> the other for four-node tetrahedra.
> I'm using Gmsh 2.3.1 on openSUSE 10.2 and Gmsh 2.2.5 as
> packaged for Ubuntu Hardy.
> (I realize this is a very old post to reply to; should I have
> started a new thread?)
>
> Geordie McBain
> http://gdmcbain.freeshell.org
>
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