Recent blog entries for kervalen

I've gotten an opportunity to combine my interest in computing with my interest in building design. And, lacking anyone to talk about it with, I've decided to start a series on computing and building design here. I'm going to begin with a discussion of current work, and move on to both software specfics and broader issues.

Some background first: the University of Oregon's Environmental Control Systems series covers HVAC (heating, ventilation, air-conditioning), lighting, and acoustics. As part of the two-course series we are expected to do two Vital Signs studies as term projects. For my first study, I did something about air-flow in a stairwell. For the second, I am now doing a project involving daylight and artificial light in a fine old library reading room; you can see some of the preliminary results here. Part of the project involves predicting lighting.

Now the usual means of doing this is to build a physical scale model and photograph it in actual daylight. But this cannot predict the combination of artificial light and daylight with any reliability; it is very difficult to build accurate working scale models of luminaires (lamps + fixtures + controls) and even more difficult to match the light that a luminaire actually puts out.

An ideal situation for computer modelling, not so? And when, back in the '70s, daylighting experienced a revival, a research effort was begun which bore fruit in a program called Radiance. Now Radiance is a strange and wonderful beast. It is an extra-ordinarily good lighting modeller; it combines radiosity and ray-tracing approaches to the prediction of radiance (which is the technical name for electromagnetic radiation coming from a point) in the visible spectrum and produces models accurate enough to use for lighting design and handsome enough to use architectural presentations.

However, Radiance is exceptionally difficult to use. I would guess there are at most 500 regular users of the system; perhaps as few as 100. These users, however, include some of the foremost engineering firms and lighting designers in the world. The difficulties with Radiance lie in two areas: compatibility with existing building modelling software and user interface.

And I think I'm going to break this off here...I will eventually get to such fun things as setting up Radiance on a Beowulf cluster and the need for an open framework for computer architectural modelling.

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