An extruder for a three-dimensional additive printer can be used to receive and dispense material. The extruder can include a number of different components including a nozzle with an adjustable opening configured to discharge material. The nozzle can be configured to be moved and rotated so as to align the adjustable opening with a plurality of paths along which the material is configured to be deposited for generating a three-dimensional object. The adjustable opening can comprise a first orifice and an obstruction member configured to move with respect to the first orifice. The position of the obstruction member can adjust the size of the opening area of the adjustable opening.