EVALUATING THE NETWORK AND USABILITY CHARACTERISTICS OF VIRTUAL-REALITY CONFERENCING

This paper presents the results of the BT-funded 'Inhabiting the Web' project which conducted a series of twenty virtual meetings using the MASSIVE virtual reality teleconferencing system between five universit ies and BT Laboratories. The aims of the project were, firstly, to ass ess the characteristics of the network traffic generated by MASSIVE an d therefore, by extension, the network traffic generated by other peer -to-peer unicast-based collaborative virtual environments, and secondl y, to identify key human factors issues arising from the long-term and regular use of such a system. The paper gives an overview of the MASS IVE system and the organisation of the meetings and then presents an a nalysis of its results. The network analysis involves a statistical an alysis of system logs in order to build a profile of typical user beha viour. This profile indicates how much users might be expected to enga ge in basic actions such as moving and speaking during a typical meeti ng and also to what extent these actions might be correlated among use rs. When combined with ail understanding of MASSIVE's network protocol s, this leads to a model to predict the network traffic generated by v arying numbers of users. It also suggests new design possibilities suc h as 'group portals', caching of worlds and tile use of multicast prot ocols. Usability reflections address the issues of embodiment, navigat ion and use of the spatial model of interaction as implemented in MASS IVE. New design possibilities are identified including higher level su pport for gestures oil embodiments and so-called object-centred and co ntext-sensitive styles of navigation.