A method is provided for treating a surface of a molded part, produced in a 3D printing method, with a surface treatment means, wherein holding means are arranged on the molded part which enable a treatment of the surface in a treatment chamber, without the surface making contact with the walls of the treatment chamber. A corresponding method for producing a molded part in a 3D printing method is also provided, as well as the corresponding dataset for controlling a 3D printer, and a computer program product which determines a number of holding means on the basis of the geometry data of the molded part.