I assume you have the Elfini extension to CATIA. It is possible to read a CATIA mesh made with Elfini into Gambit, Fluent's preprocessor, by exporting the mesh to an ANSYS tet mesh format. You'll have to use ANMANAGE, ANMESH, ANPHYSIC & ANSOLID in CATIA to accomplish this. Then Gambit can read this ANSYS mesh but with the mesh you will have only a faceted geometry, so if you want to change something in the geometry you'll have to start all over again in CATIA. Make sure your mesh is fine enough because you may have trouble defining BC's on an faceted surface that is not complete. Actually this is how I used to obtain a solid geometry in Gambit from CATIA (before I switched to using CADfix). It was possible after importing the ANSYS mesh into Gambit that I could delete the mesh (typically it was a poor mesh) and the geometry would be retained as an archival remnant, be it a faceted geometry but it was good enough for my purposes.
