CommonGround: Externalizing Mixed Reality Interfaces for Active Bystander Collaboration

Abstract

Mixed Reality (MR) expands interaction beyond traditional screens by embedding virtual interfaces within the physical environment. This affordance makes MR a powerful medium for collaboration, as users can jointly reference and coordinate around shared virtual interfaces placed in the real world. However, most collaborative MR systems assume that all collaborators have access to MR headsets or comparable devices, leaving non-MR collaborators with limited agency through indirect access mechanisms such as first-person livestreams of the MR user’s view. We present CommonGround, a collaborative MR-projection system that lets MR users externalize planar virtual interfaces onto physical surfaces using projected light and enables non-MR users to manipulate shared content through natural hand gestures. CommonGround maintains information symmetry through real-time bidirectional synchronization between headset and projected interfaces. We describe our system and outline a planned user study comparing CommonGround against a verbal-only baseline to examine its impact on various collaboration measures.