3D printing machines, namely, three dimensional (3D) printers; computer printers, namely, machines for making three-dimensional embodiments of computer-generated designs by a material deposition process and replacement parts and fittings therefor; computer software for operating and controlling computer-aided machines for making three-dimensional models and parts; computer software for creating and manipulating 3D images, models and data for making three-dimensional models and parts; computer software that transforms computer files into a physical model of a design for making three-dimensional models and parts; data and image processing software for making three-dimensional models and parts; computer software for data analysis and optimization of 3D printing processes; computer software, namely, software tools for graphic computing of 3D images, models and data for making three-dimensional models and parts; computer software, namely, image visualization software for creating 3D images, models and data for making three-dimensional models and parts; computer software, namely, image presentation software for creating 3D images, models and data for making three-dimensional models and parts; computer application software for handheld computers, namely, software for creating and manipulating 3D images, models and data for making three-dimensional models and parts; CAD/CAM software for making 3D computer models for 3D printing; computer software for 3D printing and rapid manufacturing and prototyping; computer software for converting a digital 3D model into printing instructions for a 3D printer