Thank you BlasMolero and JohnRBaker for the information ,
for BlasMolero , i do the same as you explained , i import a Nastran bulk file to NX then i use the "face from mesh" command to create polygon faces from pshell .
the question is the possibility to pass from polygon faces to just faces (*.prt) , because the editing options are larger when we work in a .prt file like creating midsurfaces and other geometry simplifying tools , even when using NX open journals the program will be more efficient for manipulating operations .
I guess i will try to work with the available options in NX 8.5 .
Thanks again .