Simulation of reflected daylight from building envelopes

With more frequent problems of reflected daylight from building envelopes, it is important to assess the influence of a building envelope design in terms of reflected daylight at early stage. This could reduce the risk of environmental problems and minimize the consequences cost after construction.
The objective of this study is development of procedures for the assessment. A tool chain has been implemented on parametric design platform RHINO and GRASSHOPPER. With the form of the building envelopes analyzed, the critical areas around the assessed building including roads, pavements and façades of neighboring buildings could be examined for reflected daylight distribution. Rich information is recorded for the critical areas: annual irradiance values contributed from the assessed envelope, period with irradiance value above a threshold, origin of the reflected daylight on the assessed building envelope, etc. This information could help designers to optimize the form and material selection of the building envelope.