ViCAT: Visualisation and Interaction on a Collaborative Access Table Fang Chen 1 , Benjamin Close 1,2 , Peter Eades 1 , Julien Epps 1 , Peter Hutterer 1,2 , Serge Lichman 1 , Masa Takatsuka 1,3 , Bruce Thomas 1,2 , Mike Wu 1 1 IMAGEN Program, National ICT Australia 2 School of Computer Science, The University of South Australia 3 School of Information Technology, The University of Sydney julien.epps@nicta.com.au ; masa@vislab.usyd.edu.au ; bruce.thomas@unisa.edu.au Abstract Despite many years of research in the area of human-computer interaction, there are still remarkably few computing platforms in existence that permit remote collaboration over various software applications in an intense manner. Visualisation and Interaction on a Collaborative Access Table (ViCAT) is a new project whose aim is to allow intense collaboration between multiple users at multiple remotely located sites, as if the users were gathered around a physical table. This paper introduces the ViCAT design philosophy and how it addresses the mixed presence groupware concept, and then describes the relationship between the ViCAT project and current horizontal interactive human-computer systems research. 1. Introduction Horizontal computing interfaces are inherently different from the desktop paradigm, in terms of user perceptions of the applications that should be used with them, the feasible input and output methods, and the opportunity for team-based rather than individual work. Horizontal interactive human-computer systems research has seen the development of a number of table-based computing prototypes, such as the metaDESK [7] and the InteracTable [3]. In this paper, we describe ViCAT, a networked computing platform that extends the notion of a physical table as a place for meeting, sharing ideas and working together in an intense manner to the world of remote collaborative computing. For the purposes of this paper, ‘intense collaboration’ refers to the shared use of a fully-fledged application where more than one user is able to enter input simultaneously (as opposed to the more common ‘chalk passing’ approach to multi-user input), while remaining aware of other users’ activities. 2. Design ViCAT’s design allows remote groups to interact simultaneously to perform a common goal. ViCAT comprises a large vertical rear-projected screen, on which the various remote collaborators are shown, and a large horizontal screen, onto which the shared application is rear-projected, as seen in Fig. 1. Using hand gestures without obscuring the projected image provides a major improvement in usability, according to informal user feedback. AccessGrid [1] is used to provide video over IP feeds of remote coworkers. cursors remote collaborators Figure 1. The ViCAT table at one of four sites, sharing a multimodal video editing application on the horizontal screen. ViCAT uses Mixed Presence Groupware [4]; this is the combination of Single Display Groupware (SDG) and Shared Display Groupware (ShDG). In SDG multiple people share one display on one machine, while ShDG users share one common desktop (or just one window) across different hosts. ShDG does not however have support for an arbitrary number of users on each host. Mixed Presence Groupware has the capability of supporting any number of users on each host in the network, while still sharing one common view on an application. It is anticipated that Mixed Presence Groupware in ViCAT will be the key to facilitating multiple simultaneous interactions, and will serve as a basis for developing new social interaction protocols to enable fluid group collaboration. Proceedings of the First IEEE International Workshop on Horizontal Interactive Human-Computer Systems (TABLETOP ’06) 0-7695-2494-X/05 $20.00 © 2006 IEEE