I've never worried about dpi when doing a 3d render. If I want something that will be ten inches square at 300 dpi, I'll render it 3000 x 3000 pixels. I could care less if Poser says it's 72, 300 or whatever. I've been using Poser for quite a while, and I think I've never changed it from it's default 72. However, once I go to Photoshop and get ready to print, I'll make sure everything is set right in that program.