Abstract: The invention relates to a gantry-type three dimensional printing apparatus for printing a three dimensional work piece in a layer wise manner using a building material, said apparatus comprising at least: a frame with an XYZ-gantry; a printing head unit coupled to said XYZ-gantry; a building material supply unit for feeding building material to said printing head unit; and a support platform on which said three dimensional work piece is being printed in layers, said support platform being part of said XYZ-gantry and is movable in the Z-direction.