A print method for printing three dimensional (3D) objects that are difficult to copy by use of a 3D scanner and 3D printer. The printer includes a print head with an extrusion nozzle with a heated portion and a print bed with a surface for receiving material extruded from the extrusion nozzle. The printer includes a print material supply spool loaded with an anti-scanning filament. The method includes operating the print head to draw the anti-scanning filament into the heated portion for heating and to extrude the heated filament from the extrusion nozzle to form a 3D object. The printed 3D object includes one or more scan protected exterior surfaces on at least one element of the 3D object. The scan protected exterior surfaces are either light absorbing or reflect light in unconventional directions. The anti-scanning filament is a plastic mixed with an anti-scanning additive such as a retroreflective material.