Abstract
Most current tabletop groupware systems use direct touch, where people manipulate objects by touching them with a pen or a fingertip. The use of people's real arms and hands provides obvious awareness information, but workspace access is limited by the user's reach. Relative input techniques, where users manipulate a cursor rather than touching objects directly, allow users to reach all areas of the table. However, the only available awareness information comes from the virtual embodiment of the user (e.g., their cursor). This presents designers with a tradeoff: direct-touch techniques have advantages for group awareness; relative input techniques offer additional power but less awareness information. In this paper, we explore this tradeoff, and we explore the design space of virtual embodiments to determine whether factors such as size, realism, and visibility can improve awareness and coordination. We conducted a study in which seven groups carried out a picture-categorizing task using seven techniques: direct touch and relative input with six different virtual embodiments. Our results provide both valuable information to designers of tabletop groupware, and a number of new directions for future research.
