i have heard that few companies doing assembly without constraining ... they are doing by only move command(NX8.5)... How can i do those things in creo? i tried move option... but i could not understand its functionality..
You end up with nothing but a "packaged" assembly, where everything is just floating in space, not constrained to anything. I would strongly advise against it. For one thing, Mechanism will NOT work, or any of the other things you can do with a properly constrained assembly.
You are comparing apples and oranges (Creo and NX).
NX can handle the moved components much better than Creo can.
We had pre-NX and early NX users you never mated their assembly components and it was not a problem. Creo does not like unmated components.