Students from K-12 can create 3D images/models by using this online drawing tool. They have a free download version for educators and kids.
http://www.sketchup.com/intl/en/download/gsu.html (download)
Have students sketch a model. They are to teach other students how to create what they created; they can create a movie describing step by step on how to make their image. This is a good idea to do collaboratively or as a project based learning assignment.