Disney BSDF
Project Overview
This project implements the Disney principled BSDF in a custom Monte Carlo path tracer (Lajolla) for physically-based rendering. Inspired by production shaders in Blender, Unreal Engine, and Renderman, the Disney BSDF unifies several reflection and transmission lobes into a single flexible material model.
The implementation includes support for five core components:
- Diffuse — retroreflective scattering with optional subsurface approximation
- Metal — Cook-Torrance microfacet model with anisotropic GGX distribution
- Clearcoat — secondary specular layer with wide lobe
- Glass — rough dielectric reflection and transmission with Fresnel effects
- Sheen — retroreflection lobe for cloth-like materials
Each lobe supports importance sampling, PDF evaluation, and physically-inspired parameterization. These components are combined following the Disney 2015 shading model, with appropriate energy weights and inside-outside logic.