Issues with scale or units in Bluebeam PDF Revu
UPDATE: This issue has been resolved in Bluebeam Revu 12. See this post
If you’d like to print PDFs to Scale using Bluebeam Revu, you’ll find instructions here.
If your measurements in Revu show at an incorrect scale or units, your PDF probably contains Viewports that were created when the PDF was published from Autocad (or another CAD program). The solution is to remove these viewport and then calibrate the PDF again.
Here are a few documents that describe the issue and the solution.
Video (courtesy of Bluebeam, Inc)