Bryce, Vue, Terragen, etc will all do it an do a much better job as far as the landscape is concerned, but the main advantage is it does it ALL WITHIN POSER, so no-one has to learn a whole new program, exporting, importing, etc. All the models remain posable and no fuss with opaque eyeballs, ditzy textures, and such. 3D worlds is actually a pretty well-designed (albeit very limited) set of terrains, atmospheres, light sets, effects, textures, and such for poser. They're fairly detailed, so they really can eat up system resources even before you start to add additional characters. If you've ever used one of Graphon's free environments, the basic principles are the same, just more developed.