SketchUp is a tool to make 3D drawings. The program needs to be downloaded and it comes in two versions (both are free for educators but in most cases you don’t need the pro version). SketchUp provides a toolset and an intelligent drawing system to make 3D modelling easy. Some of the possibilities are: Combine your own models with shared model assemblies from an online repository, render the surface and place your model within Google Earth.
With SketchUp the students can create, modify and share 3D models. It is suitable for both large and small scale models.
A quick view of possibilities:
More information: Official video tutorials