of a pressure difference between the material storage means 12 and the u201c flight space u201d for the droplets 15 portioning is effected by means of a cyclically operated aperture which is for example provided with a nozzle needle or the like as closure means as a result of the required dimensions of the portions and also of the viscosity characteristics pressures in the range from 100 mpa 1000 bar and above closure apertures of smaller than 0 1 mm and furthermore closure times of less than 0 001 s are normally necessary since the materials are mainly plastics materials melt temperatures of up to 450 u00b0 c prevail in the material storage means the discontinuous droplets 15 must be able to form under these conditions while on the other hand relatively stringent quality requirements apply to the three dimensional object 16 to be produced control means 18 therefore alternately influence as required in opposite directions the velocity and or direction with which at least one of the elements comprising object carrier 14 or three dimensional object 16 on the one hand and outlet opening 20 on the other hand are moved relative to one another with accompanying variation of the.