This is probably off track with what your asking , but for simplicity in 3d or just to have a little fun with making something in 3d take a look at this , I use it to show kids (8-12) the basics of a 3d engine , you won't make anything serious with it , but the engine is very simple and my students have made some nice little projects with it .
http://www.silentworks.hu/mk/index.php