daylightsimulating

Daylightsimulating is the computational process of modeling natural daylight within a built environment or virtual scene to predict illumination levels, visual comfort, shading, and energy use. It covers architectural daylight analysis and rendering-based simulation used in computer graphics.

In architecture, it uses sun position, sky luminance distributions, and material properties to estimate interior illuminance hourly over a year. Methods rely on ray tracing or radiosity, implemented in tools such as Radiance, Daysim, ClimateStudio, and DIVA for Rhino.

Sky models include the CIE Standard General Sky and the Perez all-weather model; sun position is derived from date, latitude, and time. Climate-based daylight modeling uses weather data to compute metrics such as daylight autonomy (DA), spatial daylight autonomy (sDA), and usable daylight illuminance (UDI) to assess targets.

Applications include optimizing window-to-wall ratio, façade shading devices, and lighting controls to reduce electric lighting while preserving comfort and reducing energy use.

In graphics and visualization, daylightsimulating informs realistic rendering of outdoor and indoor lighting, using sun-sky models such as Preetham or Hosek-Wang, or HDRI lighting for scene illumination.

Limitations include material property accuracy, occupancy behavior assumptions, and computational cost; ongoing work seeks tighter integration with building energy models and more accurate sky representations.