Google Sketchup, by far the most popular 3D modeling tool in the known universe, now has a great way to send your Sketchup model to a 3D printer. Simply install the new plugin from CADspan and you'll be able to generate solid .STL files suitable for submission to most 3D print services and printers.
The plugin provides basic 3D features only, and the resulting .STL file is completely solid. This might be ok for some applications, but probably there will be a lot of wasted print media in thick objects.
The plugin permits you to pull models from Google's very extensive 3d warehouse and prep it for 3D printing. Basically, this means "water proofing" the model so that no interior-facing surfaces are visible. In other words, you have to make the model completely water-tight so that it can become "solid". The plugin uses easy visual coloring effects to help you through this potentially tedious process.
Another interesting feature we noticed was that you can not only export your model as .STL, but you can also import .STL as well.