The rapid prototyping framework presented in this chapter provides fast, simple and inexpensivemethods for the design and fabrication of prototypes of robotic mechanisms.As evidenced by the examples presented above, the prototypes can be of great help togain more insight into the functionality of the mechanisms, as well as to convey theconcepts to others, especially to non-technical people. Furthermore, physical prototypescan be used to validate geometric and kinematic properties such as mechanicalinterferences, transmission characteristics, singularities and workspace. Actuated prototypes have also been successfully built and controlled. Actuated mechanisms can be used in lightweight applications or for demonstration purposes. The main limitation in such cases is the compliance and limited strength of the plasticparts, which limits the forces and torques that can be produced. Finally, several comprehensive examples have been given to illustrate how the rapidprototyping framework presented here can be used throughout the design process. Two robotic hands and a SLA machine model demonstrate a wide variety of link and jointfabrication methods, as well as the possibility of embedding sensors and actuators directlyinto mechanisms. In these examples, rapid prototyping has been used to demonstrate,validate, experimentally test (including destructive tests), modify, redesign and,in one case, support the machining of a metal prototype. 43.