Virtual reality (VR) is a rapidly proliferating technology whose usability is constantly on the increase. Some applications of VR technology have already matured, meanwhile others are still in their infancy. VR offers new possibilities in the .eld of product development by speeding up the pace and improving quality and usability. Three of the main applications of VR that present valuable opportunities for product development in general are: simulation, skills training, and communication with distributed colleagues or third parties (e.g. users, experts, and customers). With VR technology, prototypes and products can be tested ‘virtually‘ (socalled virtual prototyping) before .nal veri.cation with physical prototypes is performed. Additionally, users can ‘virtually‘ test and train the use of the products before they exist, which can lead to improved usability and better ergonomic design. Customers and users can interactively inuence the features of a product idea and the layout plans (e.g. for a factory, a hospital, or a city) by using VR. Especially for the development of complicated and even complex radical new products, the author recommends that brain-aided design and pencil-aided design, perhaps followed by model-aided design (MAD) should most often be carried out before VR is used. Ideally, for innovative product development, computer- aided design (CAD) should be used .rst after the modelling with MAD and/or VR has provided their contributions. For re-engineering, when CAD .les exist, PAD is still supportive while MAD is often not needed because VR in that case uses existing CAD .les, eventually after reversed engineering or scanning of paper drawings has been carried out.