This article presents the methodology used in the initial versions of the web-based dynamic daylight simulation tools and compares the results with those from Radiance using the exact same model. It is intended as a detailed supplement to a research paper with a similar title submitted to the PLEA 2017 Conference in Edinburgh, providing additional explanatory material, information and results to support the arguments made in the original paper.
The freely available RADIANCE software is one of only a few lighting analysis tools able to accurately calculate illuminance levels on surfaces within a building model. This article explains how illuminance levels can be used to generate daylight factors in RADIANCE and presents a number of ways of doing this, including using ECOTECT as a modelling interface. It also shows how both illuminance levels and daylight factors calculated in RADIANCE can be read back and displayed interactively within your ECOTECT model.