IMRCE: A Unity Toolkit for Virtual Co-Presence

In this paper we present the design, implementation, and evaluation of IMRCE, our immersive mixed reality collaborative environment toolkit. IMRCE is a lightweight, flexible, and robust Unity toolkit that allows designers and researchers to rapidly prototype mixed reality-mixed presence (MR-MP) environments that connect physical spaces, virtual spaces, and devices. IMRCE helps collaborators maintain group awareness of the shared collaborative environment by providing visual cues such as position indicators and virtual hands. At the same time IMRCE provides flexibility in how physical and virtual spaces are mapped, allowing work environments to be optimised for each collaborator while maintaining a sense of integration. The main contribution of the toolkit is its encapsulation of these features, allowing rapid development of MR-MP systems. We demonstrate IMRCE's features by linking a physical environment with tabletop and wall displays to a virtual replica augmented with support for direct 3D manipulation of shared work objects. We also conducted a comparative evaluation of IMRCE against a standard set of Unity libraries with complementary features with 10 developers, and found significant reductions in time taken, total LOC, errors, and requests for assistance.