I am searching for a software program (freeware if possible), which can read prt-files from Unigraphics and transfer it into iges (or dxf) for input into Gambit.

Unigraphics should be able to export iges, but this is not a good format for some reason.

Try to export in ACIS format. This you can read much better into gambit and you dont loose any accuracy.

Otherwise export it in the parsolids format, read it into Solidworks and export it in the ACIS format.

Hi,

parasolid to iges is not such a good idea: you will loose all the beauty of solid modelling. Moreover, Gambit does not like iges geometries; you will get all your geometry as a virtual one, which means that you will be able to perform a very limited amount of operations on your virtual geometry. Try to translate the parasolid formatted file (unigraphics) to an ACIS one. An other option would be to translate your parasolid file to a STEP one. There exists a free STEP-ACIS translation service on the STEP homepage. Some says that STEP-ACIS is better than IGES-ACIS.

Good luck and let me aware whether it worked or not.

Thank you for your help, your message led me to the right way to solve my problem. But let me explain, that the key problem is that I can not save my CAD graphics in any other format but prt, because I don't have a license for the unigraphics file exchange module. So I needed an extern translator from prt to acis (or iges, or step, etc.), and I found such a translator in the program parasat plus (15 days trial version can be downloaded at http://www.compunix-usa.com/), which can read parasolid files and transfer them to acis.