Am I allowed to publish a 3d scan of a statue/thing I bought?
If the design was made from an artist and is not public domain, than you should not upload that scan without the (written) permission of the creator of the design. Espacially a scan of a decorative object will likely be protected, so costumers buy the original instead of printing itself or buy a printed version. If you would design a deco object and sell copies of it, you also don't want that others just scan it and print it.