Hi mford610,
No idea about the current 3D PDF (I’m since a while in a chat with Adobe, trying to find more, but I got transferred …), even if it is since a long an option in Acrobat. Check current concerns about safety. I think it was first available over a decade ago. I was always a huge fan of PDF—since the ‘90s, and have helped to implement it in many companies. So, yes, interesting question, to check the current procedure and options again.
Adobe tells this, but I saw other information about this as well:
https://helpx.adobe.com/acrobat/using/adding-3d-models-pdfs-acrobat.html
As this differs
https://helpx.adobe.com/acrobat/kb/supported-file-formats-acrobat-reader.html
Edit: I had three different people in the chat, the most conclusive is answer is, you need “Acrobat Pro DC”, whereby the normal “All Apps” subscription does not includes it. The “Acrobat Pro DC” monthly seems to be ten bucks more. Please check all of that, so you get the solution you need. /edit
The normal Acrobat Pro might allow 3D but only with very specific formats. None of those formats are included in C4D exports.
Some Adobe forums pages suggest MeshLab for conversations. You might test this carefully, it is an open source application and you’re on your own with that, I do not suggest this, I only quote others. Certainly test this in an absolute non production environment/offline computer first; I’m serious with this.
https://helpx.adobe.com/acrobat/using/adding-3d-models-pdfs-acrobat.html
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Perhaps this will work for you?
https://www.cineversity.com/vidplaylist/sketchfab_cinema_4d_exporter/
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(The data-base error, is known and worked on. It has hit other websites as well. I copy my post before I press Submit, BTW.)
Cheers