NX nastran Integrated vs Seperate package. Clarification

[ninjaz]

I have worked in Nastran NX that is integrated with UG NX software. And also worked with integrated solver-Model Solution which is in I-deas SDRC.

My doubt is, whether if i have a .dat file and need to feed in NAstran solver seperately, then do i need to feed so many codes. Or it is as simple as it is integrated with some pre-processing softwares.