Framework and software to build large scale digital city for virtual walking / cycling system

Dementia is one of the most serious problems in aging society. Aerobic exercise has good evidence for its prevention. Walking and cycling are popular and practical aerobic exercises. However, elderly people have problems in the walking and cycling, which come from lacks of physical / mental functionalities and unsuitable traffic environment. To provide safe and human-friendly environment for walking / cycling, we have developed virtual reality walking / cycling system. In this paper, a framework, which can easily and rapidly construct large-scale computer graphic data for the systems, was described. As an application, we reported about the trials for the psychophysics experiment on the traffic environment with the framework.