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-   -   Catia geometry (http://www.cfd-online.com/Forums/fluent/27501-catia-geometry.html)

Althea February 17, 2000 10:00

Catia geometry
 
Hello,

Can anyone out there make any recommendations on the creation or modification of Catia models for import into Gambit.

We currently are plagued with errors and problems and don't know how to overcome them. At the moment I have to virtually recreate the geometry everytime. I don't know what to suggest to our design engineers to reduce the problems.

We use IGES as the intermediate format.

Best regards Althea

joern Beilke February 17, 2000 11:20

Re: Catia geometry
 
use the vda instead of iges

icem-cfd is able to deal with this kind of horrible surfaces. i dont think that gambit is the right choice there.

Althea February 18, 2000 06:00

Re: Catia geometry
 
Thanks Joern,

But what is the vda and how do I import it into Gambit (which is currently my only option)?

Regards

Althea

Joern Beilke February 18, 2000 06:35

Re: Catia geometry
 
VDA is a format which is similar to IGES. The VDA converter within CATIA should produce better results than the IGES converter but it requires an additional license.

Even the VDA data from CATIA consists of not connected patches with gaps and holes.

I dont see a way to use these data within Gam(e)bit. But there are a lot of companies around with the special knowlege how to deal with this problem (generating grids from Catia data with suitable tools). But this is not for free.

Anders Tenstam February 24, 2000 13:34

Re: Catia geometry
 
Hi, What dimension convention did you use in Catia? meter or millimeter?

I had the same problem myself, and at that time the problem was propably based on the tolerance definitions used by Catia and Gambit, respectively. I had created the Catia model in mm, and upon iges conversion in Gambit with the conversion factor 1, nothing seemed to be correct (intersection points did not coincide etc.). I tried to import the iges file using 0.001 as conversion factor (to get meters), but that was no good either. Using 0.0001 or less, though, helped me that time. Perhaps scaling the whole thing in Catia first with a factor of 0.001 (so you get dimensions in m)and then importing it with a factor of 1 is an even better idea.

Regards Anders

Joern Beilke February 25, 2000 08:39

Re: Catia geometry
 
Did you use solid or surface medelling in Catia?

Anders Tenstam February 25, 2000 09:12

Re: Catia geometry
 
Surfaces/faces. I believe that Catia's Iges translator doesn't support solids.

/Anders


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