Hello, I am new to shapeways and have been working on my first project. A ring, for a really good friend of mine with inscriptions. since it is a ring I need to file to be printed just as I created it in CAD, or it wont fit, however when I do this, the dimensions are not accurate and the ring is either too large or too small. What am I doing wrong here? It is a .stl file exported from Autodesk Inventor. I tried meters, inches, and (mm? whatever the third option was) but none are correct. thanks you I will attach the file if it helps..