Abstract: A carousel system includes a platform and a plurality of material delivery systems mounted on a periphery of the platform, each respective material delivery system including a first gear and an extruder nozzle head. The carousel system also includes a carousel rotatably mounted on the platform, a first motor adapted to cause the carousel to rotate from a first radial position to a second radial position, a second motor mounted on the carousel, a drive shaft coupled to the second motor, and a second gear coupled to the drive shaft. Engagement of the second gear with one of the first gears causes the corresponding material delivery system to force an amount of a selected material into the corresponding extruder nozzle head, heat the selected material to soften the selected material, and deposit the selected material on a surface. Each material delivery system provides material having a respective color. The carousel system may be used in a 3D printing system.