We describe a novel system for rapid prototyping of laserbased optical and holographic layouts. Users of this optical prototyping tool-called the Illuminating Light systemmove physical representations of various optical elements about a workspace, while the system tracks these components and projects back onto the workspace surface the simulated propagation of laser light through the evolving layout. This application is built atop the Luminous Room infrastrncture, an aggregate of interlinked, computer-controlled projector-camera units called Z/O Bulbs. Philosophically, the work embodies the emerging ideas of the Luminous Room and builds on the notions of ‘graspable media’.

We briefly introduce the VO Bulb and Luminous Room concepts and discuss their current implementations. After an overview of the optical domain that the Illuminating Light system is designed to address, we present the overall system design and implementation, including that of an intermediary toolkit called voodoo which provides a general facility for object identification and tracking. Keywords