This paper presents a new complete CAD-driven rapid prototyping system for polystyrene. ModelAngelo, as it is called, consists of six subsystems featuring hardware and software. The system utilizes a virtual 3D CAD model to produce a set of commands used to control a 5-axis CNC Machine to move a heated-wire tool into a block of polystyrene to form the desired surface. The ultimate goal of ModelAngelo is to reach the stage of “what you see is what you get”. An overview of ModelAngelo system is first presented followed by a detailed discussion of ModelAngeloSoftware. The various mechanical subsystems responsible for realizing the final product are then described. Advantages and disadvantages of several tooltip designs are discussed and the best solution is selected. The main features of the robotic arm, which carry the tooltip is also discussed in detail. Finally ModelAngelo controller that manages the interaction between software and hardware is briefly highlighted and possible applications of ModelAngelo are suggested.