Abstract: A viscous flow thermoplastic film is extruded as a variant thickness profile curtain by means of an extrusion die having a flow choke rod extending longitudinally parallel with the die jaws and positioned within one die jaw for chordal projection into the die flow channel. The choke rod is surface relieved by chordal flats at locations corresponding to film zones of greater thickness. A single rod may be provided with as many profile pattern sequences as space and dimension allows chordal segments around the rod circumference. Pattern selection may be changed under die running conditions by rotating the profile rod about its axis to align the flats of the desired pattern within the die flow channel.