Here’s another way to make a 3D PDF, this time with all native Autodesk products.

  1. Use Virtual Agent to download Inventor Publisher 2015 trial
  2. Export a view from Revit (or 3dsMax, or AutoCAD, or Navisworks) as FBX that you would like to make into a 3D PDF
  3. Start Inventor Publisher
  4. New file
  5. Select the FBX
  6. Orient the imported FBX in the view and use the Viewcube to Set Current View as Front or Top as appropriate
  7. On the Home Ribbon under Publish, choose Adobe PDF
  8. Select 3D PDF
  9. Save the file

It makes very decent quality 3D PDFs, with good colour representation.

Idea via:
http://forums.autodesk.com/t5/revit-architecture/3d-pdf/td-p/2843148

Then you can download Autodesk Inventor View 2014.

Share native Autodesk® Inventor® software data with non-Autodesk Inventor users with this freely distributable viewer that delivers high-fidelity viewing and printing of parts, assemblies and drawings.

Important: Ensure you download and install the version of Inventor View 2014 appropriate for your operating system. Additionally, you should not install this software on a computer that already has Autodesk Inventor 2014 software installed.

Autodesk Inventor View 2014 (32bit) (exe – 672610Kb)

Autodesk Inventor View 2014 (64bit) (exe – 774802Kb)

Readme (htm – 24Kb) 

via Autodesk – Autodesk Inventor View 2014

Update Release 1 is not a full install; rather it is using service pack technology similar to AutoCAD®- based products. Prior to installing the Update Release 1, please verify that you have already installed the First Customer Ship build of Autodesk Inventor 2014.
You can apply this update to Autodesk Inventor 2014 running on all supported operating systems and languages. Consult the readme file for installation instructions and be sure to install the correct update (32-bit or 64-bit) for your software and operating system.  This Update Release improves data integrity and visual fidelity when exchanging models with Revit.

Readme (select language version):

English (htm – 29Kb)

via
Autodesk – Autodesk Inventor Services & Support – Revit Interoperability for Inventor 2014 – Update Release 1