On Navigation Guidance for Exploration of 3D Environments

Report, 2006

Navigation in complex and large-scale 3D virtual environments has been shown to be a difficult task, imposing a high cognitive load on the user. In this paper, we present a comprehensive method for assisting users in exploring and understanding such 3D worlds, computing first a complete path through the world used as a basis for exploration and then supporting the rich interactions necessary for navigating and wayfinding in the world. The method consists of two distinct phases: an off-line computation step deriving a grand tour using the world geometry and any semantic target information as input, and an on-line interactive navigation step providing guided exploration and improved spatial perception for the user. The former phase is based on a voxelized version of the geometrical dataset that is used to compute a connectivity graph for use in a TSP-like formulation of the problem. The latter phase takes the output tour from the off-line step as an input for guiding 3D navigation through the environment using a technique we call spring-zooming. A user study indicates a significant efficiency improvement in performing visual search tasks in a complex 3D environment using the technique in comparison to unaided 3D navigation. Furthermore, the results show that the spring-zooming technique strikes a good balance between guidance and interaction, achieving significantly better general recall performance in comparison to a simple tour-following technique allowing for no user control.