Physical Model, Heliodon Testing: Direct Beam Illumination Patterning
In this mode of testing a model is placed under a theatrical spotlight on a specially articulated tabletop that turns, tilts and rotates to simulate the beam and shadow effects of the sun as it arcs through the sky during various times of the day, month and year. By observing the sun and shadow patterns on the scaled model, designers can evaluate and make decisions about the placement and size of windows, skylights, overhangs and other shading and sun control devices. This type of testing is primarily observational rather than quantitative. In addition to highly accurate modeling of sun and shadow patterns, the general direct beam component and any reflections can be observed in the absence of the sky vault component of the sky’s influence. Ground reflectance and/or interruption of the direct beam component are represented by physically modeling any nearby surfaces that would have significant reflecting or shading influences on the area under study. Observation of these patterns is enhanced by the use of a pencil-sized remote head video camera that can be inserted into the model to give the client an immersive first-hand preview of sunlight patterns inside or outside of the finished building. Images from the camera can be viewed in real-time on a video monitor, captured for later review and analysis and even broadcast over the internet for analysis by personnel at remote locations. Typically a strategic testing approach is formulated that samples representative times of the day, month and year for key building spaces and points of view. Heliodon testing can also qualitatively inform decisions about thermal comfort and glare.