I use downloaded stuff in Poser, and "home made" stuff in Bryce (when it's working - lost my serial number and had to reinstall D'oh!) because I'm not much of a modeller, but Bryce is good for simple terrain and geometric shapes. You can use any images you create from the "base" figures for free - the only problems come when you attempt to redistribute the figures in any form. Other figures usually include explicit licensing agreements, which vary from creator to creator.