Annon said:
SketchUp works pretty good, they've got a demo on their site I'm pretty sure. It may not fit your needs, but it doesn't hurt to try the demo.
+1
Sketchup is excellent and written natively on a Mac (I use the PC version at work
). What are you going to school for? Sketchup is an excellent 3d DESIGN/Visualization tool...but it it not for fully rendered models (no ray tracing or no light sources other than the "sun") or for detailed working drawings for architects or engineers. However, for quickly building a model there is nothing better out there right now from a speed, simplicity, and preice point of view.
Plus it workg great on a Mac!! BTW you can export/import with Autocad pretty well.