[Gmsh] Meshing STL File

[jbi35 at student.canterbury.ac.nz]

Hello Christophe,

I am currently seeking information about the algorithm used in gmsh. I had a look at your homepage but did not find anything. I found a couple of papers on the tetgen homepage explaining the algorithms they used, is there something similar available for gmsh??

kind regards 
Jonas Biehler


 On Tue  1/07/08 11:16 PM , Christophe Geuzaine cgeuzaine at ulg.ac.be sent:
> jbi35 at student.canterbury.ac.nz wrote:
> > Hello Christophe,
> 
> > 
> 
> > yes I can send you the stl files with which the problem
> occurs. Please find two stl files
> > of the same geometry but different element sizes
> attached to this email
> 
> 
> Hi Jonas - The problem comes from the STL import: since there is no
> 
> connectivity in STL files, Gmsh has to use a geometrical tolerance to
> 
> determine when vertices are identical.
> 
> 
> 
> The default tolerance is a bit to large in your case, resulting in nodes
> 
> being merged that shouldn't have been. Add
> 
> 
> 
> Geometry.Tolerance = 1.e-12;
> 
> 
> 
> at the begining of your .geo file: it will decrease the tolerance and
> 
> should fix the problem.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> > 
> 
> > kind regards
> 
> > jonas biehler
> 
> > 
> 
> > 
> 
> > 
> 
> >  On Thu 19/06/08  6:12 PM , Christophe Geuzaine cgeuzaine
> @ulg.ac.be sent:
> >> jbi35 at student.canterbury.ac.nz wrote:
> >>> Hi there,
> 
> >>> i am currently using gmsh to create 3d volume meshes
> 
> >> from an stl file, which describes the surface. In
> order to create meshes
> >> with different mesh sizes i can create finer or
> coarser surface meshes(
> >> stl's) The problem is that gmsh does not work for some
> mesh sizes
> >>> e.g it works for 0.002 and 0.0022 but not for 0.0019
> or
> >> 0.0021.
> 
> >>> Has anybody had similar problems in the past ? Or
> knows
> >> a remedy??
> 
> >>
> 
> >>
> 
> >> Could you send me the files? I cannot reproduce this
> problem with our 
> >>
> 
> >> benchmark suite.
> 
> >>
> 
> >>
> 
> >>
> 
> >>
> 
> >>
> 
> >>
> 
> >>
> 
> >>> thanks for your help
> 
> >>> cheers jonas
> 
> >>>  
> 
> >>> _______________________________________________
> 
> >>> gmsh mailing list
> 
> >>> gmsh at geuz.org
> >>> http://www.geuz.org/mailman/listinfo/gmsh
> >>>
> 
> >>
> 
> >>
> 
> >>
> 
> >>
> 
> >> -- 
> 
> >>
> 
> >> Prof. Christophe Geuzaine
> 
> >>
> 
> >> University of Liege, Electrical Engineering and
> Computer Science
> >>
> 
> >> http://www.montefiore.ulg.ac.be/~geuzaine
> >>
> 
> >>
> 
> >>
> 
> 
> 
> 
> 
> -- 
> 
> Prof. Christophe Geuzaine
> 
> University of Liege, Electrical Engineering and Computer Science
> 
> http://www.montefiore.ulg.ac.be/~geuzaine
> 
> 
> 
> 
>