Virtual Heliodon: Spatially Augmented Reality
for Architectural Daylighting Design

Abstract: We present an application of interactive global illumination and spatially augmented reality to architectural daylight modeling that allows designers to explore alternative designs and new technologies for improving the sustainability of their buildings. Images of a model in the real world, captured by a camera above the scene, are processed to construct a virtual 3D model. To achieve interactive rendering rates, we use a hybrid rendering technique, leveraging radiosity to simulate the inter-reflectance between diffuse patches and shadow volumes to generate per-pixel direct illumination. The rendered images are then projected on the real model by four calibrated projectors to help users study the daylighting illumination. The virtual heliodon is a physical design environment in which multiple designers, a designer and a client, or a teacher and students can gather to experience animated visualizations of the natural illumination within a proposed design by controlling the time of day, season, and climate. Furthermore, participants may interactively redesign the geometry and materials of the space by manipulating physical design elements and see the updated lighting simulation.

Physical model	Virtual model

	7am	9am	12pm	2pm	5pm
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Jun 21st
Dec 21st

Spatially Augmented Reality for Interactive Daylighting Visualization

See also:
RPI Computer Graphics Group
Research Project: Architectural Daylighting

This work was also supported by a grant from IBM.

This material is based upon work supported by the National Science Foundation under Grant No. CMMI 0841319. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.