[Gmsh] Feature request/question

Christophe Geuzaine cag32 at case.edu
Mon Apr 24 02:19:50 CEST 2006


F.Caner wrote:
> Hello Christophe,
> 
> I am using gmsh for about 4 months now, and I think it is very nicely
> written; especially the idea of a .geo file appeals to me a lot.
> 
> One type of element that I use quite often is called ``interface
> element" that is made up of two coincident surfaces; the constitutive
> law is prescribed as a function of relative displacement of these
> surfaces, and stresses are integrated over either bottom or the top
> surface. That element cannot be generated using gmsh in a
> straightforward manner.
> 
> Right now I am using gmsh with Geometry.AutoCoherence=0, so that I can
> have two volumes with a common surface but with duplicate nodes; then I
> use a python script to generate elements out of the matching nodes. Of
> course, this also requires the two volumes to have their common surface
> mesh to be aligned. All these I am trying to get using python scripts.
> 
> By now I started to think this effort is really too much, yet there is
> no better option than gmsh, and eventually I am thinking that may be
> this can be programmed into gmsh.
> 
> I am wondering how difficult it could be; in case it is not that
> difficult, I am willing to offer my service to this end; or better yet,
> if you could easily do it, I (and many other people) would be grateful.
> 

Hi Ferhun - Do you need to actually have duplicate nodes in the mesh 
file? If not, you can simply define multiple Physical Surfaces on the 
interface: this will lead to multiple surface elements "on top of each 
other" in the .msh file (using the same nodes).



> Best,
> 
> Dr. Ferhun Caner
> School of Civil Engineering
> Universitat Politecnica de Catalunya
> Barcelona
> Spain.
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-- 
Christophe Geuzaine
Assistant Professor, Case Western Reserve University, Mathematics
http://www.case.edu/artsci/math/geuzaine