Bidirectional Reflectance Distribution Function (BRDF)

The Bidirectional Reflectance Distribution Function (BRDF) describes how light is reflected off a surface. It defines how much light is reflected in each direction when light hits a material from a specific angle. Think of it as a detailed map that tells you, for any incoming light direction, how the surface will scatter that light into different outgoing directions. BRDF helps in understanding and simulating realistic appearances of objects—like shine, gloss, or matte finish—by accurately modeling how surfaces interact with light in various viewing and lighting conditions.