An integrated design system (IDS) approach has been developed to integrate various stages of the mechanical design process, including rapid prototyping. The system consist, of design, analysis, calculation, rapid prototyping, and library modules, and it blends artificial intelligence methods, CAD-CAM, and technical computing packages into a single environment. The system has been applied for the design of one-stage gearbox with helical gear. In this case study, all stages of the design process are carried out by using IDS.