A binary STL file was generated using the STL plug-in from AutoDesk for Revit Architecture 2013. The measurements within the resulting STL file do not match the size of the component modeled in Revit. There is no mention of setting the scale within the online help text provided with the STL plug-in that I could find. The component in the Revit file measures 17.875 inches in the longest axis but the component within the STL file measures only 1.490 inches in the long axis. The scale in Revit 2013 is set at 12"=1' as the component was modeled and the STL was generated. This behavior looks like a bug. The measurements in the STL file must match what was created in Revit 2013 so that the component printed by the 3D Printer is created at the modeled size, not 12x smaller. What scale setting must be specified to ensure that the resulting STL includes measurements that exactly match those modeled within the Revit file?