Hi Brent,

I have had (and posted) this problem, and still have it.
What has been done AFAIK is that a functionality which should in principle do 
what we need has been implemented in gmsh, developped by Mark van Doesburg. But 
it works only in some cases (e.g. plane surfaces). If you want to try it, check 
"Tools->Options->Geometry->Cut and merge faces (experimental)", reload your 
geometry and see what happens.
I had thought for a while that the geometry healing functionality of Netgen 
could solve the problem, but it does not, at least not in 3D.
I am actually working on a solution of the problem, but I don't know yet what 
it will be. I see two possibilities:

1. Switch to another preprocessor. I evaluate GiD at the moment, which is not 
free, but not so expensive either. As far as i have found out so far, it can 
collapse the surfaces. But I still have some technical problems, i.e. GiD 
crashes sometimes for complicated geometries. If this problem cannot be solved 
by the GiD people, I have to opt for solution 2.

2. Program something myself. I have actually started to write a mesh processor. 
The idea is to take the 2D mesh (e.g. generated by gmsh), identify touching 
surfaces, merge them, reload the cleaned up mesh in gmsh, re-define the 
volumes, and generate the 3D mesh. For the moment, my program just reads and 
orders the mesh. I will continue to work on it as long as the GiD problem is 
not solved.

That's the status from my point of view.

Matthias


----------------------------------------------------------------
ERBE Elektromedizin GmbH
Dr.rer.nat. Matthias Zenker
Dipl. Phys.
Grundlagenentwicklung / Fundamental Development
Waldhoernlestrasse 17
72072 Tuebingen
Germany
Phone + 49 (0) 7071 755 - 226
Fax + 49 (0) 7071 755 - 5226
E-Mail: <mailto:[email protected]>
URL: http://www.ERBE-med.com
----------------------------------------------------------------

-----Ursprüngliche Nachricht-----
Von: Vandevender, Brent A [mailto:[email protected]] 
Gesendet: Donnerstag, 31. März 2011 02:57
An: [email protected]
Betreff: [Gmsh] importing .step files with multiple parts whose surfacestouch

I have looked through the mailing list archives and found that a couple of 
years ago some people were actively developing the capability to "sew" together 
the common surfaces of parts that touch each other (i.e., have a common 
surface).  I have also seen more recently that those same people have declared 
that effort a failure.  I wonder what is the current status of this capability 
in gmsh in case I have missed something.

I am trying to import the attached .step file made by our MEs so that I can do 
finite-element electric field modeling.  In the attached model there are 2 
pieces, one should be a conductor and the other a press-fit insulator.  GMSH 
makes a beautiful 2D surface mesh, but the common surface consists of two 
meshes.  I think what I really need is for there to be just one mesh at the 
interface for subsequent 3D meshing and solving with getDP.  I have tried some 
options, Geometry.OCCSewFaces = 1 and Geometry.OCCConnectFaces = 1, with no 
success.  OCCConnect Faces at least recognizes the common surfaces in my model, 
but rather than merge them into one, it removes them both.  I am sure this has 
come up for others on the list, and I wonder what solutions people have figured 
out, if any.


--
Brent A VanDevender, PhD
Pacific Northwest National Laboratory
Radiation Detection and Nuclear Sciences Group

email:[email protected]
phone:509-371-7982


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