An important but neglected aspect of virtual prototyping is the interaction between human and digital prototype. This is an essential issue when tests about ergonomics or product safety are required. This paper presents an approach to evaluate product ergonomics and safety based on the use of virtual human and simulations where the human model interacts with the virtual prototype. Two case studies that can demonstrate the validity of the approach are described. The first concerns the instruments and external visibility of a car; geometric model of the interior and a commercial virtual human have been used. We defined a test methodology and several simulations have been made, varying anthropometry and workplace adjustments. The results obtained are images that represent what the virtual human sees and permit to evaluate the validity of design solutions. The second case study regards the ergonomics design of a riveting system and consists of the simulation of operator's tasks using a virtual workstation and a virtual human. The results are the joint angles that define the posture of the operator and permit one to analyse task comfort. This work has been carried out to demonstrate that virtual humans are an important tool to improve virtual prototyping functionalities and, above all, to increase ergonomics and safety of products. Moreover, the second case study demonstrates also that this methodology is today necessary not only in big industry, but in small-medium enterprises too.
