HdRestir 0.f — GGX Materials and Spectral Paths
Once rays can find surfaces, the renderer needs a material model that behaves consistently across direct lighting, indirect transport, and sampled wavelengths. HdRestir resolves MaterialX closures into a compact representation and evaluates them through a regularized GGX model.
The article connects the BSDF equations to the implementation, including evaluation and sampling, spectral throughput, emission, direct-light contribution, and the practical safeguards that keep difficult materials numerically stable.
