In General also Make sure you are making smaller animations that you will stitch together later. I also second the recommendation of outputting as bitmaps. (These are good ideas in any 3d animation software.) So far I've only been doing test animations in P5, with 2-3 clothed mill figures and not much else. I think the longest I have done thus far was 200 or 300 frames. and I havn't had any hangs yet. Hopefully I'm one of the lucky ones... But I'll be very interested to see if I start having problems when I get down to my real project.