I work for a surgeon who wants to have videos created about different procedures. He would like the work I create for him to legally stay his own. For the most part these would be the videos. If I were to use ZAnatomy, would we still be able to protect his videos as his own IP or would it have to fall into CC BY-SA 4.0 as well? I doubt he'd have a problem with needing to credit the initial author of the model, but he doesn't want other people to be able to distribute the content that he's paid for, be it models or videos I create or changes I make to the existing model.