Metalog Materials

Information

• Publication Type: Journal Paper with Conference Talk
• Workgroup(s)/Project(s):
  • Toward Optimal Path Guiding for Photorealistic Rendering
• Date: November 2026
• Journal: ACM Transactions on Graphics
• Volume: 45
• Open Access: yes
• Note: Hiroyuki Sakai and Saip-Can Hasbay are joint first authors
• Location: Kuala Lumpur, Malaysia
• Lecturer: Hiroyuki Sakai
• Event: SIGGRAPH Asia 2026
• Conference date: 1. December 2026 – 4. December 2026
• Pages: 182:1 – 182:13
• Keywords: material modeling, BRDF representation, importance sampling, Monte Carlo rendering, physically based rendering, metalog distributions

Abstract

A central aspect of modern physically based rendering is the practical yet realistic modeling of material appearance, which requires efficient and accurate representations of bidirectional reflectance distribution functions (BRDFs). In this paper, we present a unified material reflectance representation based on metalog distributions. Introducing quantile-based metalog interpolation and metalog mixture models, our representation captures a wide range of complex reflectance behaviors of both analytic models and real-world materials, while remaining interpretable and efficient. Our approach achieves competitive runtime performance and a small memory footprint, while enabling continuous interpolation between fundamentally different reflectance behaviors. Furthermore, our model is fully differentiable with respect to the coefficients defining the distributions, thus easily integrates into existing differentiable rendering pipelines. In summary, metalog materials can effectively represent real-world reflectance data, interpolate between multiple materials within a unified representation, and be acquired from real-world images via differentiable rendering.

Additional Files and Images

Weblinks

• Project Page

BibTeX

@article{sakai-2026-mm,
  title =      "Metalog Materials",
  author =     "Hiroyuki Sakai and Saip Can Hasbay and Christian Freude and
               Michael Wimmer and David Hahn",
  year =       "2026",
  abstract =   "A central aspect of modern physically based rendering is the
               practical yet realistic modeling of material appearance,
               which requires efficient and accurate representations of
               bidirectional reflectance distribution functions (BRDFs). In
               this paper, we present a unified material reflectance
               representation based on metalog distributions. Introducing
               quantile-based metalog interpolation and metalog mixture
               models, our representation captures a wide range of complex
               reflectance behaviors of both analytic models and real-world
               materials, while remaining interpretable and efficient. Our
               approach achieves competitive runtime performance and a
               small memory footprint, while enabling continuous
               interpolation between fundamentally different reflectance
               behaviors. Furthermore, our model is fully differentiable
               with respect to the coefficients defining the distributions,
               thus easily integrates into existing differentiable
               rendering pipelines. In summary, metalog materials can
               effectively represent real-world reflectance data,
               interpolate between multiple materials within a unified
               representation, and be acquired from real-world images via
               differentiable rendering.",
  month =      nov,
  journal =    "ACM Transactions on Graphics",
  volume =     "45",
  note =       "Hiroyuki Sakai and Saip-Can Hasbay are joint first authors",
  pages =      "182:1--182:13",
  keywords =   "material modeling, BRDF representation, importance sampling,
               Monte Carlo rendering, physically based rendering, metalog
               distributions",
  URL =        "https://www.cg.tuwien.ac.at/research/publications/2026/sakai-2026-mm/",
}