Thanks, that got me to look in the right place. As of the
latest Terms doc , looks like there is no basis for this though. The content sharing section says:
Sharing Your Content and Information
You own all of the content and information you post on Facebook, and you can control how it is shared through your privacy and application settings. In addition:
1- For content that is covered by intellectual property rights, like photos and videos (IP content), you specifically give us the following permission, subject to your privacy and application settings: you grant us a non-exclusive, transferable, sub-licensable, royalty-free, worldwide license to use any IP content that you post on or in connection with Facebook (IP License). This IP License ends when you delete your IP content or your account unless your content has been shared with others, and they have not deleted it.
2 - When you delete IP content, it is deleted in a manner similar to emptying the recycle bin on a computer. However, you understand that removed content may persist in backup copies for a reasonable period of time (but will not be available to others).
3 - When you use an application, the application may ask for your permission to access your content and information as well as content and information that others have shared with you. We require applications to respect your privacy, and your agreement with that application will control how the application can use, store, and transfer that content and information. (To learn more about Platform, including how you can control what information other people may share with applications, read our Data Policy and Platform Page.)
4 - When you publish content or information using the Public setting, it means that you are allowing everyone, including people off of Facebook, to access and use that information, and to associate it with you (i.e., your name and profile picture).
5 - We always appreciate your feedback or other suggestions about Facebook, but you understand that we may use your feedback or suggestions without any obligation to compensate you for them (just as you have no obligation to offer them).
Sounds like you are more or less making it public though. It gets deleted you remove it, but anyone who could see it could have copied it. That looks to be more of an issue with images, not 3D models, since I doubt it can easily be done. While it seems Facebook also gets it, it is also bound by privacy in a different section.