At ACADIA 2008, in Minneapolis. Daniel Belcher presented "MxR: A Physical Model-Based Mixed Reality Interface for Design Collaboration, Simulation, Visualization and Form Generation," a paper based on his Master's Thesis research project and co-authored by Brian R Johnson. The project was blogged by Spatial Robot (http://www.spatialrobots.com/archives/432) (which includes links to YouTube video), and Digital Urban (http://digitalurban.blogspot.com/2008/10/mxr-architecture-mixing-physical-and.html).