Letters
Lighting Design Software
In the guest article by Pertola and Svedenius (Lighting Design software: Not Yet Good Enough, IAEEL Newsletter 1/95), PC-based software that is "not yet good enough" receive great attention in favor of time-proven lighting design "software". While exemplary daylit buildings around the world pre-date the introduction of electric lighting, there is currently no consensus on what constitutes a daylit building, let alone exemplary examples.This is true despite the abundance of data concerning daylight availability, room-finish product characteristics, electric lighting hardware and control systems, and (rapidly outdated) PC-based software to assess all of the above. Instead, it is posited that re-mastery of the "low-tech", "high-touch" capabilities of the human visual system and memory would again prove more than enough for architectural lighting design purposes. I suggest freehand drawing and water-color rendering as proven and cost-effective means for examining alternatives in theory and practice. Finally, I very much appreciate your efforts made in putting together this valuable newsletter.
Glenn Sweitzer
Department of Architecture
University of Tokyo, Japan
Reply: Essentially, Glenn Sweitzer understood one of our basic messages correctly: lighting design software is "not yet good enough". But we believe that he draws the wrong conclusion.
We agree that lately there have not been many good daylit buildings erected. However, this is not due to a shortage of talented lighting software programmers or to designers ignoring the abundance of data available. Nor can the blame be placed on limitations of present lighting design software programs. The problem can, instead, be ascribed to the fact that since the good old days of exemplary daylit buildings, when architects and builders knew how to use "time-proven" daylighting methods (such as good rules of thumb, model building, and water-color renderings), the buildings have changed a lot: They are now tremendously more complex, primarily owing to the increasingly diversified needs of the users.
There is no doubt that we need an abundance of data to be able to design an economically sound, energy-efficient and ecologically sustainable building that also meets all the needs of today's demanding users. But we also need profound knowledge of the subject itself-light-to be able to handle such data. This will be the case with or without lighting design software. We believe that knowledge in the area of light and daylighting is generally very poor among architects, engineers, and programmers, with few exceptions. Instead of going back to those time-proven methods, which assume that pigment diluted in water on a paper can somehow be used to understand the flow dynamics of solar energy within a building, we strongly advise all parties involved in lighting design to develop their knowledge base. In particular, it is important that courses for tomorrow's lighting designers offer more comprehensive knowledge in this area.
Peter Pertola
Lighting Designer
PELK AB, Stockholm, Sweden
Nils Svendenius
Assistant Professor,
Dept. of Physics
University of Lund, Sweden