First-person experience and usability of co-located interaction in a projection-based virtual environment

Large screen projection-based display systems are very often not used by a single user alone, but shared by a small group of people. We have developed an interaction paradigm allowing multiple users to share a virtual environment in a conventional single-view stereoscopic projection-based display system, with each of the users handling the same interface and having a full first-person experience of the environment.Multi-viewpoint images allow the use of spatial interaction techniques for multiple users in a conventional projection-based display. We evaluate the effectiveness of multi-viewpoint images for ray selection and direct object manipulation in a qualitative usability study and show that interaction with multi-viewpoint images is comparable to fully head-tracked (single-user) interaction. Based on ray casting and direct object manipulation, using tracked PDA's as common interaction device, we develop a technique for co-located multi-user interaction in conventional projection-based virtual environments. Evaluation of the VRGEO Demonstrator, an application for the review of complex 3D geo-seismic data sets in the oil-and-gas industry, shows that this paradigm allows multiple users to each have a full first-person experience of a complex, interactive virtual environment.