It has to do with the settings in the Adobe Reader. If you are using anything other than Adobe Reader you will have other issues as well. At the moment I cannot remember the exact setting that needs to be changed (no 3D PDF file on this computer), but I think it is on the 3D Multimedia page under preferences. I believe it is the "Preferred 3D PMI...." drop down selection.
The clip above is found insider of Adobe Reader under 'Edit>Preferences"