I played around in Art of Illusion, it has quite sophisticated features and the help system/documentation was useful for getting started: http://artofillusion.o

I played around in Art of Illusion, it has quite sophisticated features and the help system/documentation was useful for getting started: http://artofillusion.org/ http://artofillusion.org/ Bryce 3D is another tool that comes to mind with a UI that is easy to grasp, but more for generating awesome raytraced landscapes and floating mirror cubes :)