Please can someone offer some help to resolve this pesky normals issue. I have tried about 20 tests this evening, about 19 of them on my original wheel rim mesh, all failed with the "Your model has inverted normals in it" error. I don't know how this can be, as the model appears fine in 3ds max. I decided to go back to the drawing board and produce a simple version. I uploaded this simplified model (56mm diameter, 23.5mm height), and still got the error. There is nothing fancy in this mesh, so I am now officially flummoxed. I'm loving Shapeways (got a couple of items from other modelers earlier this week), but getting over these hurdles is proving almost insurmountable. Can anyone please shed some light as to what might be causing this? I have attached a DAE file in mm units and can supply other formats if requested.