You can get an idea of things people have designed and printed by visiting thingiverse.com. The size constraints for the Makerbot are basically 10 cm by 10 cm by 10 cm. Anything larger will have to be resized or designed as multiple pieces. For information about overhangs, designing supports, and such wall thickness check out Design Guidelines for Makerbots.
Once you have designed your object in Google Sketchup, you need to export it using the STL plugin.
- Under the Tools menu select Export to DXF or STL.
- If you don't have anything selected, it will ask if you want to export the entire model. You do.
- Select Millimeters as the export unit.
- Select stl on the Choose which entities to export window.
- Save the stl file somewhere that you'll remember, this is the file you'll send to us for printing