Google Sketch-up is an online program where you can create 3D models. There is a searchable repository, Google 3D Warehouse where you can explore models.
Why UDL?
>"Google SketchUp 7 is a great tool for students to help them to better visualize spatial concepts and supports multiple means of representation.
> Google SketchUp is also ideal for students who may have poor fine motor skills but need an alternative way to demonstrate their understanding of a concept or an idea and supports the notion of multiple means of expression."