BRDFn

BRDFn is a term that refers to a Bidirectional Reflectance Distribution Function, specifically a parameterized or approximated version thereof. In computer graphics and rendering, the Bidirectional Reflectance Distribution Function (BRDF) is a fundamental concept used to describe how light reflects off a surface. It quantifies the ratio of reflected radiance to incident irradiance, taking into account the direction of incoming light and the direction of outgoing light.

Exact mathematical representations of BRDFs for real-world materials are often complex and computationally expensive to evaluate. Therefore, in practice, BRDFs are frequently approximated or parameterized using mathematical models. BRDFn, as a general term, signifies such an approximation or a specific implementation of a parameterized BRDF model. These models typically use a set of parameters to capture the diffuse and specular reflection characteristics of a surface, allowing for more efficient rendering. Examples of common BRDF models include the Lambertian model for diffuse reflection and various specular reflection models like Phong or Blinn-Phong. More advanced models also incorporate parameters for roughness, anisotropy, and other surface properties to achieve more realistic visual results. The goal of using a parameterized BRDF is to balance visual fidelity with computational performance.