[Gmsh] Bug report and a question about Gmsh

Gael de Bressy de Guast gael.bressy at sergi-holding.com
Thu Feb 8 11:00:12 CET 2007


First of all, I'd like to thank you for developping a tool as Gmsh. I just recently discovered it and I must admit that the program is very easy to use, performs well in all kind of situation and gives very satisfying results when it comes to meshes. 

Until now, I was using Gmsh to generate 2D meshes from a geometry I defined using the built-in CAD tool. I'm now trying to import a more complex 3D geometry in order to build a volumic tetrahedra mesh. This means that I cannot create the geometry myself and import models from other CAD tools, such as SolidWorks.

Alas, it seems that I have encountered a bug ! While opening a .STP file, Gmsh 2.00 sent me back to the desktop with this error message (in gmsh-errors) :


Info    : Reading 'C:/Gaël/Mailleurs non structurés/Exemples de Maillages/Cube avec Tore inclu dedans.STEP'
Fatal   : Segmentation violation (invalid memory reference)


Then, when importing an IGES file, there is no volume defined, which implies that no 3D mesh can be created, only 2D elements. When I try to modify the geometry in order to add a volume (elementary entities>add>new>volume) by selecting a surface loop, the program returns :


Error   : Unknown surface 8
Error   : Unknown surface 8
Info    : Surface Loop(1) = {8};


This implies that the renumbering of elementary entities from an imported file is not stable, or not written in the program memory.  Obviously, there is an algorithm that translates imported features into Gmsh own language. This can be seen when passing the mouse over the geometry, the dialog bar returns the name of the feature, its number and the list of features that compose it. 

Knowing this, is it possible to easily translate an .igs file into a .geo file without the 'merge' command ?

I'll keep you informed if I ever come across another bug or if I have another comment. Thanks again for spending your time developping this wonderful tool and I hope my comments will help you improve it even further.


Gaël de BRESSY
SERGI Research Department
186, avenue du Gal de GAULLE
P.O. Box 90 - 78260 ACHERES - FRANCE
Tel: 33 - 1 39 22 37 18 / Fax: 33 - 1 39 22 48 55
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