The Geometrical Design of Light-Environment of “Komorebi” with the Application of Two-Dimensional Grid Measurements of Illuminance

“Komorebi” is a Japanese term that describes dappled sunlight filtered through the branches and leaves of trees. Natural phenomena such as Komorebi give rise to natural and comfortable environments. For example, it is known that Komorebi has positive effects on relieving psychological stress. There are a lot of projects that are applied such comfortableness and naturalness of Komorebi to architecture, lighting, and other designs. However, most of them are still confined to conceptual imitations and not based on quantitative indicators. In this paper, the time series data of in-plane illuminance in Komorebi were recorded by multi-point simultaneous measurement of 4 x 4 grid, and the two-dimensional features of illuminance in Komorebi were visualized by spectral analysis. Furthermore, a geometrical design of lighting equipment that generates the in-plane fluctuation characteristics of the Komorebi as sequences of discrete illuminance quantified from measurements was proposed through multi-objective optimization with a genetic algorithm utilizing the results of measurements as the objective function.