I am puzzled. When I uploaded the dae file to Shapeways, it was accepted, but parts of it disappeared. What confuses me most is that the parts that are missing are actually thicker than parts that showed up. Why did this happen, and what can I do to correct it? Here is a link to my model. It is supposed to be a set of bleachers, like at a ballpark. The posts showed up, as did the safety rails, but the seat planks and foot planks are gone. I can send someone the dae or original Sketchup file if they want to check it out. Thank you.