You need to use this method.

You just need to use this method.  The important part is setting your referrer (Referring Page) to

This is about 21 gig in total… has an extended post on how to view Revit files for free at this link:
Autodesk – Autodesk Revit Viewer Free

The page reviews the following methods (none of which are very exciting):

For Revit files There are various possibilities.

Display native Revit files
  • Revit installation in viewing mode
Viewing exported data
  • Viewing DWF in Autodesk Design Review
  • DWF viewing in Internet Explorer
  • DWF Viewing into NavisWorks
  • Viewing in NWD NavisWorks Freedom

The English equivalent to the .de page is considerably shorter: