Autocad import into Gambit
 

I have a model that I wish to import into Gambit to "clean up" and mesh before analysis in Fluent. The 3D wireframe model was constructed in Autocad 14 and saved as a .dwg file. On trying to import it into Gambit, with the import option of ASCI, the result is a blank screen with the journal box reading of

0 ASIC body, 0 faces, 0 vertices, 0 blocks imported.

So the question is what am I doing wrong? Is Autocad a ASIC format or do I have to save it as a differnent format. Or is there something wrong with the drawing that Gambit doesn't recognise?

Thanks in advance

Paul

Re: Autocad import into Gambit
 

(1). I think there is a "generation gap" problem. Autocad was invented in 70's when people was using PC/286 for 2-D drawing. It was so popular that their format became the standard. (2). Gambit program was invented recently and it is a combination of 3-D CAD and mesh generation for Fluent codes. I am not sure what is exactly used in the program. (3). I hope that there is a simple solution to this generation gap problem. But, the guideline I always use is that " use the complete series of programs from one company only, even if you don't like one of the program in the series". This will eliminate the interface problems between two codes from two companies developed in two generations.

Re: Autocad import into Gambit
 

I believe Gambit uses the ACIS solid modeling kernal. The requirement is for solid, manifold geometry to be imported. Autocad R14 also uses ACIS and so will be able to export a .sat file (Spatial's native file format).

Interfacing will always remain a problem as commercial codes will have to support as many interfaces to commonly used CAD packages as possible. This is easier to do via neutral file formats than via direct interfacing. Commonly used neutral file formats include SAT, IGES, STL, STEP.

Steve.

Re: Autocad import into Gambit
 

I think that Gambit wants to get a solid body and not a wireframe.

Re: Autocad import into Gambit
 

(1). Yes, Autocad R14 uses ACIS solid model. I found a short sentense on it in a Autocad book from a bookstore. (2). I am sure that Gambit also uses ACIS solid model.

Re: Autocad import into Gambit
 

If you have wireframe geometry in AutoCAD you can only import IGES file into GAMBIT. (IGES translator is not included in AutoCAD R14, but is in AutoCAD R12, so one more step is needed=import DWG file which is saved in format of R12 in AutoCAD R14 into AutoCAD R12). If you have solid geometry in AutoCAD then import ACIS file into GAMBIT. The only possible communication between AutoCAD and GAMBIT is with IGES and ACIS files. You cannot import DWG files.

Pavel