To the best of my recollection, they didn't invent anything. At best, they might have had some royalty or other rights agreement with the folks who invented, owned, and had used those special 3D cameras.
For your historical background, several years back there was a European corporation that proposed to deliver 3D video over satellite. They tempted Da Boyz by inducing them to provide content. Neither the 3D satellite people nor Da Boyz had any money. That 3D satellite idea went away. At the time, I had a C-Band analog satellite system; I picked up the 3D network in trials. To the best of my knowledge, it wasn't either true 3D transmission or reception.
Somebody correct me if I am wrong, but the most promising 3D opportunities were probably 3D XXXX sexual pornography for the hotel and brothel trade. Had Da Boyz gone in that direction and would have been exposed, the bible-thumping sycophants who pump here might not have been happy. Note, the term "might" was chosen; many of the supporters of this story stock would cheer for any move Da Boyz made if it would potentially move the price per share of this stock upward. LOL.