[Gmsh] howto import STEP/IGES/BREP file?

Mireille Gaillard m92l29e91 at laposte.net
Thu Feb 21 09:36:17 CET 2008


Hello to all,

On the same topic, the use of IGES/STEP/BREP files, I also have a
question. I could import correctly the geometry .iges, but when asking
to mesh in 3D a fatal error forced Gmsh to abort and quit. This occur
when Gmsh try to mesh in 2D (no error for meshing in 1D) due to
"Segmentation violation (invalid memory reference)".


I work with the executable file Gmsh (not compiled on my own system) on
a labtop ACER under GNU/Linux Suse 10.3. I have attached the error file
.gmsh-errors.

Thank you for any advises on how to proceed to mesh in 3D an imported
.iges file.

Mireille

Christophe Geuzaine a écrit :
> Edgar Last wrote:
>> Thanks for the solutions how to configure gmsh with opencascade support 
>> and how to import a STEP file.
>>
>> Now I wonder how I can set the characteristic lengths in an imported 
>> geometry. Is there no documentation how to use the import feature? I 
>> will probably have many more questions about what shapes can be meshed, 
>> mesh control etc. Do I need to take the source code for the only 
>> "documentation"?
> 
> Using a nightly snapshot, you have many options:
> 
> 1) Specify a global scaling factor (using e.g. "-clscale" on the command 
> line). When no char. lengths are provided (which is the case when you 
> load a normal STEP file), a default length of "object_size/10" is used. 
> Using "-clscale 0.1" will divide this default length by 10.
> 
> 2) Specify a min and/or a max char. length, using the "-clmin" and 
> "-clmax" command line options.
> 
> 3) Compute the char. length automatically from the curvatures, using 
> "-clcurv".
> 
> 4) Use a background mesh (see tutorial/t7.geo).
> 
> 5) Merge your STEP file in a GEO file, and use all the char. length 
> modification options available in the .geo language. In addition to the 
>   options given above (for example, 
> "Mesh.CharacteristicLengthFactor=0.1;" in a GEO file  is the same as 
> "-clscale 0.1" on the command line), you have also full access to char. 
> lengths associated with points, function-based size fields, etc.
> 
> 
> 
>> Btw, I am now using the precompiled gmsh version from the gmsh website, 
>> which is fine for the moment. The configure options you suggested didn't 
>> have any effect. I used:
>> ./configure --enable-occ --with-occ-prefix=/opt/local/opencascade
>> Configure produced no output at all mentioning occ, is this to be 
>> expected? Compilation was successful, but no import possible. This is 
>> not a severe problem right now, because I can use the precompiled 
>> binary. However, I'd like to be able to compile with occ support. How 
>> can I find out why configure doesn't recognize occ?
>>
>> Edgar
>>
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> 
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