Embodiments for Mixed Presence Groupware

Large surfaces such as tabletop and whiteboard displays naturally afford collocated collaboration, where multiple people work together over the shared workspace. As large digital displays become more ubiquitous, it becomes increasingly important to examine their role in supporting groups of distributed collaborators working over the digital work surface. In particular, Mixed Presence Groupware (MPG) is software that connects both collocated and distributed collaborators and their disparate displays via a common shared virtual workspace. We have built several MPG systems by connecting several distributed displays, each with multiple input devices, thereby connecting both collocated and distributed collaborators. By observing how these systems are used, we found that MPG presents a unique problem called presenc1e disparity: collaborators focus their energies on collocated collaborators at the expense of their distributed counterparts. Presence disparity arises because the physical presence of collaborators varies across the MPG workgroup: physically collocated collaborators are seen in full fidelity, while remote participants are represented by only virtual embodiments. Consequently, we propose four design principles for MPG systems that we believe will help mitigate the problem of presence disparity in MPG. We then introduce how these principles are realized in VideoArms, an embodiment technique that digitally captures people’s arms as they work over large work surfaces, and redisplays them as digital overlays on remote displays. Our evaluation of VideoArms validates its use in principle as an effective embodiment technique for MPG systems.