Virtual prototyping - State of the art in product design

Digital mock-ups (DMU) are the platform for Virtual Prototyping (VP). Therefore, questions concerning VP are focused on the integration of computer-based tools and methods for DU. Which reliability concerning the assessment of product characteristics do digital mock-ups have? What kind of representation/visualization in necessary to achieve a high reliability concerning the assessment of product characteristics of digital mock-ups? Which possibilities do we have to interact with the digital mock-ups directly? To find valid responses to the mentioned questions we have to look to immersive projection technology (IPT) systems.