Real-world objects are generally not copyrightable, unless they fall into one of the categories in which copyright law defines, such as sculptures, buildings, and "works of artistic craftmanship". If it's just a rock, or a mass-produced car part, it's unlikely to be copyrightable. Hence it would follow, at least to me, that a mechanical 3D scan of the object wouldn't be copyrightable either, since it has no originality.