Export a file from solid works to Unigraphics Nx 6

What would the best 2D and 3D formats be if we had to export a part file from solid works to Unigraphics Nx 6. I have tried some of the popular formats like .stf, igs, dxf dwg but the file does not open in unigraphics Nx6. Is there a universal format that all softwares can run ?

SolidworksImport export