First thing to do is get a lawyer skilled in copyright law as applicable where you live. It's going to depend in no small part on whether your scanned model is considered a copy or a transformative work of art.
Personally, I see scanning an object as similar to photographing it (or sketching it). Lots of art objects, or for that matter personal items such as a photo of a living person, are protected by copyright; others aren't. If I made the laws, which I sadly don't :-) , I would consider a scanned, printed object to be in the same boat as a sketch -- has to be demonstrably transformative and all that.