Hybrid Ray-tracing and Radiosity Method


Ray tracing and radiosity are both popular algorithms used to predict indoor daylighting distributions. Ray-tracing algorithms are appropriate when surfaces have ideal specular properties; whereas radiosity-based methods are suitable when dealing with diffuse properties (Lambertian surfaces). In the developed hybrid method, the ray-tracing method is used to capture the specular characteristics and the radiosity method is used to capture the diffuse characteristics of surfaces. The surfaces that have strong diffuse characteristics (such as a common interior wall) are only solved by the radiosity method. For surfaces that have both diffuse and specular characteristics,  the incoming luminous flux is split into an anisotropic part (specular), which is processed the ray tracing method, and an isotropic part (diffuse), which is processed using the radiosity method.