CAD tip # 8646:

1. Install the version for Inventor 2013 from Exchange Apps or from the CAD Studio Download page.
2. Copy the file

   C:\Users\{username}\AppData\Roaming\Autodesk\ApplicationPlugins\CAD Studio Inventor Anaglyph.bundle\Contents\CADStudio.AnaglyphCreatorAddin.Inventor.addin

   to the file

   C:\ProgramData\Autodesk\Inventor 2012\Addins\CADStudio.AnaglyphCreatorAddin.Inventor.addin

3. Open this file in Notepad or other text editor (not MS-Word!)
4. Edit the seventh line from

   < Assembly>AnaglyphCreatorAddin.dll< /Assembly>

   to

   < Assembly>C:\Users\{username}\AppData\Roaming\Autodesk\ApplicationPlugins\CAD StudioInventorAnaglyph.bundle\Contents\AnaglyphCreatorAddin.dll< /Assembly>

5. Save the file.

Note: replace {username} with your profile name in the paths; the XML markup < Assembly> should have no space