The brief stint I had with Poser5, it is by default set to render with the Firefly engine - you CAN change that setting and tell Poser5 to render using the Poser4 engine, but there's going to be certain things/effects that you are able to do in P5 that probably wont' render, I'd think. Not positive - I only had about a week's stint with P5 on my brother's machine before I decided I really REALLY did not like it and kept on with my P4... ~Seliah