Default settings of Adobe Acrobat Reader come with disabled 3D content, which prevents Cortona3D publications from being displayed properly. To enable 3D content, go to Edit -> Preferences -> check "Enable playing of 3D content".
The following setting is also required to prevent various errors with playback of 3D PDF produced with RapidAuthor (Edit > Preferences > Security (Enhanced) > uncheck "Enable Protected Mode at Startup").
When 2 or more instances of 3D PDF files are needed to be opened at once, you may experience problems with playback and other features. To resolve this please disallow tabs (Edit > Preferences > General > uncheck "Open documents as new tabs in the same window") within the Acrobat Reader settings.