Hi fellas While exporting one of my models from Max5 into STL format, I came upon the following little but realy annoying bug. I´ve exported the model to STL and checked it in Accutrans for water-tightness and manifold errors. Accutrans warned me that I had edges with 3 or more faces connected to them, which means shapeways will reject my file, as it is a manifold error. After spending 3 hours systematicly checking all the objects in my model one by one, I localized the cause of the error. I had made a grill looking thingy in my model, which consists of many simple boxes placed side by side, each placed geometrically exactly beside the other one, with no overlap. When exporting only one column, Accutrans showed no errors, but when exporting the whole grill or multiple connecting rows and columns, it showed a manifold error. This was caused by the exporter somehow welding these perfectly positioned boxes to each other, causing the manifold error. It is not visible in Accutrans, and I was stupid enough not to check the exportetd file in Max, so as this was about the only thing perfectly built in my model I checked this as the last part. I could solve this problem by modifying all the boxes and placing new ones overlapping each other, this way there was no manifold error. The same "bug" (feature?) occured while exporting to DXF. I hope this little story helps you in your next "manifold error" hunt!