The .stl file I uploaded to Shapeways looks different than my model. The model shown in Shapeways has an added flat, circular piece in the center that is not part of my original build. My design is an open ring shape. What causes this? How can I delete the extra piece before placing order? The arrow in the attached image points to the circular piece shown in shapeways version of my model. Help is greatly appreciated.
There is at least one hole (probably many) somewhere on the rim of that pendant, and shapeways' site software tried to fix it automatically, inadvertently joining vertices across rather than along the opening. Get netfabb studio basic (freeware) from netfabb.com and use its "analysis" function to see the faults in the stl. A short tutorial on fixing holes with this software can be found on the webpage of resident forum wizard stonysmith at stonysmith.com/wired/Netfabb_Tutorial_2/default.asp