focousing on unconstructed grid how to convert the model from Gambit to Star CD ? use (*.igs) or (*.neu ) ? or another way can be done? thank you for help.

Well why do you want to convert surfaces? They are hard to handle in star. Better convert surface mesh.

so you recommend (*.neu)? but I sitll don't know how to do it(the process)?

Hi there, here is the process:

In gambit: Solver -> Generic File -> Export -> Mesh (Assign a file name, *.neu)

In Star-CD: Write the following command: gambit *.neu

I hope this helps.

God blessing! thank you.I have done it for your help .thanks a lot really.