So I'm doing up my first model is Netfabb. I'm self taught so bear with me. I have drafted initially in Google Sketchup and converted the files to STL format and used the repair feature to clean them up. But to use the files at shapeways they need to be a single shell, and I am not sure how to combine shells in Netfabb.
If someone could help me out or point me to another printer that allows multiple shells.