One of the signiﬁcant advantages of using computers in the model making early stages of the design development process is that it is possible to create and modify forms and structuresthat would be very difﬁcult to do with physical models,especially designs based on complex organic geometry.However, if CAD had provided an effective substitutefor physical scale models, there would be no need formodels made using CAD/CAM technology and yet theyare produced in an increasingly widespread manner.CAD/CAM modelling can be a full-size operation, makingprototype parts from a given material and this is commonin a number of design and engineering disciplines.Architects by the virtue of the size of buildings often usethis technology to model scaled-down representations oftheir designs but may also make full-size prototypes. SomeCAD/CAM processes, such as those using a laser or router,are subtractive in that they remove material from a sheetor block to leave the relevant elements behind and in thissense are essentially a carving technique. By contrast, otherprocesses are additive and involve the incremental buildup of layers of material. An example of this latter process isa 3D printed model that is formed topographically. Whilstthere are clear beneﬁts to the speed and precision CAD/CAM offers to modelmaking, it is very important to see itas another tool to use towards a ﬁnal model rather than acomplete package for every aspect of your design.