9 Accessories for 3D printers used for making 3D objects by additive material deposition, namely, print heads for 3D printers; software for operating and controlling 3D printers; software for use in receiving and manipulating 3D model file data for fabrication of 3D objects on a 3D printer; software used for transmission of 3D file data for printing on a networked 3D printer; software for operating and monitoring a network of 3D printers; software for use in analyzing 3D model geometry, additive deposition instructions, feedstock consumption, job cost, job duration, pricing, sharing, online displaying and ordering of parts, prototypes, and models for 3D designing, 3D printing, and manufacturing for personal and commercial use