I have a Model which Shapeways seems to be having problems with. I got the message - "Unfortunately, we were not able to process and thus print your product. Sadly we were not able to determine what exactly is wrong with it in an automated way. We have already tried correcting the issue using our Mesh Medic. " Now looking at it in Netfabb it appears to have 9 shells when it should only have one. Running the repair script appears to fix it and reduces it to 1 shell, but gives me no indication of where the extra shells where so I can go back to the original design and try any work out what is generating them. Any ideas how I can find them ? Stl file attached.