It's so interesting that the 3D PDF format that my team at Right Hemisphere helped create and establish with Adobe, is now, years later making a resurgence.
While I was VP Engineering at Right Hemisphere we partnered up with Adobe to create this 3D PDF standard and add support to Adobe Acrobat.The technology was (and still is) pretty good, the key however is that PDF makes so much sense as a collaboration standard, all it was missing was 3D, so this is why we added it.
Unfortunately since then Adobe seems to have near abandoned support for authoring the format. It's still a published Standard but Adobe hasn't added support to their iOS mobile viewer (which today is near essential). Thankfully however Techsoft3D has stepped up and is supporting it and providing a library for 3D PDF publishing.
In addition, there are other providers like Quadrispace and Tetra4D providing products to help create 3D PDFs.
Right Hemisphere in the meantime has been purchased by SAP and is now powering the SAP Visual Enterprise. They also have some excellent products that are well worth a review (which also publish high quality collaborative 3D PDFs).
If you'd like to find out more, ping me at Jed (at) 4Dpipeline.com