Additive fabrication refers to a group of technologies used for building physical models, prototypes, tooling, nished components, and production parts directly from 3D computer-aided design (CAD) data or 3D data generated using various measuring methods (such as coordinate measuring machine [CMM], computed tomography [CT], magnetic resonance imaging [MRI], or laser scans) . Different from conventional material removal processes, additive fabrication produces parts through the adding and joining of liquid, powder, or wire materials layer by layer as per the cross sections of a 3D model. Due to the nature of the technology, additive fabrication provides the capability to produce complex 3D shapes with delicate features (such as an enclosed cavity, very small internal features, etc.) that are difcult or even impossible to manufacture using conventional manufacturing processes (such as machining, casting, forming, etc.).