System and method for providing three-dimensional object structural support with a multi-nozzle extruder

An additive manufacturing system comprising:

• a multi-nozzle extruder having a faceplate with a plurality of nozzles;
• a plurality of valves, each valve in the plurality of valves being configured to open and close one of the nozzles in a one-to-one correspondence;
• an actuator operatively connected to the multi-nozzle extruder, the actuator being configured to move the multi-nozzle extruder in a plane parallel to the faceplate that has a pair of orthogonal axes that define a 0°, 180°, 90°, or 270° path of movement for the multi-nozzle extruder in the plane and to move the multi-nozzle extruder toward and away from a surface on which the multi-nozzle extruder emits extrusion material;
• and
• a controller operatively connected to the plurality of valves and the actuator, the controller being configured to:
• operate more than one valve in the plurality of valves to open more than one nozzle in the multi-nozzle extruder;
• and
• operate the actuator to move the multi-nozzle extruder along a path in the plane parallel to the faceplate at one of a 45°, −45°, 135°, or −135° direction with reference to the orthogonal axes to form with material extruded simultaneously from the more than one open nozzle a first group of multiple parallel ribbons of support structure outside a perimeter of a layer of an object being formed on the surface.