Computer simulation in daylight design: a comparison

Four of the leading computer lighting simulation programs are compared with physical modelling techniques as a means of predicting daylighting of interior spaces. Lightscape (v3-l.l), RadioRay (v2.0), Microstation/J (v7.1Beta) and ADELINE (v2.0NT) are compared with a physical model under two types of artificial sky. The analysis covers three main aspects of operation; physical accuracy of the output, visual quality of the renderings and user interface of the software. With the exception of RadioRay, the software investigated calculates daylight factors within an average of30% of those produced by a physical model. This is within an estimated experimental error of between 25% and 40% depending on location in the room. The visual quality of the output is variable with ADELINE producing the most compelling results. This paper continues to suggest where improvements to the existing technology may lie particularly in reference to interface design