An implementation of the method of aperture meridians for the ISO/CIE standard general sky

The use of the new ISO/CIE Standard General Sky offers some new challenges for lighting designers. The MAMmodeller package described in this study provides a user-friendly tool for visualizing each of the SSLD 15 models in simple design contexts. The method of aperture meridians (MAM) provides a relatively simple geometric framework to estimate the appearance of the sky as a luminance map in the window opening, as seen from a point of interest inside the room. In addition, the total horizontal illuminance at the same point is estimated. This provides the user or designer with a quick tool for undertaking preliminary design investigations. MAMmodeller is not a complete lighting design tool, it considers only sunlight and the diffuse light component from the sky entering through the window opening. It does not account for internal reflections, artificial lighting, or external reflections.