No, I need to create an environment at runtime. Absolutely.
My game is enterely procedurally generated.
Want an example? Well, check out the game I already made using Unity3d at:

http://www.massivecreek.com/home/

http://www.massivecreek.com/home/?page_id=231

I need to make the second chapter (another adventure, more complex).
So I was checking 3DGS features to make a game like this.

Thank you.