Create, present and share 3D models as images or movies, with Google Sketchup
Google SketchUp will help you create, share and present 3D models, such as a house deck, models for Google Earth, or geometry models for your class.
You can export an image, make a movie or print out a view of what you made.
There is also a commercial (Pro) version of SketchUp, if you need more features.
Google SketchUp is well designed and convenient.