“A practical extension to microfacet theory for the modeling of varying iridescence” by Belcour and Barla

  • ©Laurent Belcour and Pascal Barla




    A practical extension to microfacet theory for the modeling of varying iridescence


Session Title: Reflectance & Scattering



    In this work, we introduce an extension to microfacet theory for the rendering of iridescent effects caused by thin-films of varying thickness (such as oil, grease, alcohols, etc) on top of an arbitrarily rough base layer. Our material model is the first to produce a consistent appearance between tristimulus (e.g., RGB) and spectral rendering engines by analytically pre-integrating its spectral response. The proposed extension works with any microfacet-based model: not only on reflection over dielectrics or conductors, but also on transmission through dielectrics. We adapt its evaluation to work in multi-scale rendering contexts, and we expose parameters enabling artistic control over iridescent appearance. The overhead compared to using the classic Fresnel reflectance or transmittance terms remains reasonable enough for practical uses in production.


    1. Attila Akin. 2014. Pushing the limits of realism of materials. http://blog.maxwellrender.com/tips/pushing-the-limits-of-realism-of-materials. (2014).Google Scholar
    2. P. Beckmann and A. Spizzichino. 1963. The scattering of electromagnetic waves from rough surfaces. Pergamon Press; [distributed in the Western Hemisphere by Macmillan, New York]. https://books.google.fr/books?id=QBEIAQAAIAAJGoogle Scholar
    3. Max Born and Emil Wolf. 1999. Principles of Optics (7th edition ed.). Cambridge University Press. Google ScholarCross Ref
    4. R. L. Cook and K. E. Torrance. 1982. A Reflectance Model for Computer Graphics. ACM Trans. Graph. 1, 1 (Jan. 1982), 7–24. Google ScholarDigital Library
    5. Tom Cuypers, Tom Haber, Philippe Bekaert, Se Baek Oh, and Ramesh Raskar. 2012. Reflectance Model for Diffraction. ACM Trans. Graph. 31, 5, Article 122 (Sept. 2012), 11 pages. Google ScholarDigital Library
    6. D. S. Dhillon, J. Teyssier, M. Single, I. Gaponenko, M. C. Milinkovitch, and M. Zwicker. 2014. Interactive Diffraction from Biological Nanostructures. Computer Graphics Forum 33, 8 (2014), 177–188. Google ScholarDigital Library
    7. Disney. 2011. BRDF Explorer. https://www.disneyanimation.com/technology/brdf.html. (2011).Google Scholar
    8. Serkan Ergun, Sermet Önel, and Aydin Ozturk. 2016. A General Micro-flake Model for Predicting the Appearance of Car Paint. In Eurographics Symposium on Rendering.Google Scholar
    9. Sergey Ershov, Konstantin Kolchin, and Karol Myszkowski. 2001. Rendering Pearlescent Appearance Based On Paint-Composition Modelling. Computer Graphics Forum 20, 3 (sep 2001), 227–238. Google ScholarCross Ref
    10. Xavier Granier and Wolfgang Heidrich. 2003. A simple layered RGB BRDF model. Graphical Models 65, 4 (2003), 171–184. Google ScholarDigital Library
    11. Ole Gulbrandsen. 2014. Artist Friendly Metallic Fresnel. Journal of Computer Graphics Techniques 3, 4 (2014), 64–72. http://jcgt.org/published/0003/04/03/Google Scholar
    12. Stephane Guy and Cyril Soler. 2004. Graphics Gems Revisited: Fast and Physically-based Rendering of Gemstones. ACM Transactions on Graphics 23, 3 (Aug. 2004), 231–238. Google ScholarDigital Library
    13. JM Hammersley and KW Morton. 1956. A new Monte Carlo technique: antithetic variates. In Mathematical proceedings of the Cambridge philosophical society, Vol. 52. 449–475. Google ScholarCross Ref
    14. Xiao D. He, Kenneth E. Torrance, François X. Sillion, and Donald P. Greenberg. 1991. A Comprehensive Physical Model for Light Reflection. In Proceedings of the 18th Annual Conference on Computer Graphics and Interactive Techniques (SIGGRAPH ’91). ACM, New York, NY, USA, 175–186. Google ScholarDigital Library
    15. Eugene Hecht. 2001. Optics (4th edition ed.). Addison-Wesley.Google Scholar
    16. Isabelle Icart and Didier Arqués. 1999. An Illumination Model for a System of Isotropic Substrate- Isotropic Thin Film with Identical Rough Boundaries. In Eurographics Workshop on Rendering, Dani Lischinski and Greg Ward Larson (Eds.). The Eurographics Association. Google ScholarCross Ref
    17. Wenzel Jakob. 2010. Mitsuba renderer. (2010). http://www.mitsuba-renderer.org.Google Scholar
    18. Wenzel Jakob, Eugene D’Eon, Otto Jakob, and Steve Marschner. 2014. A comprehensive framework for rendering layered materials. ACM Transactions on Graphics 33, 4 (jul 2014), 1–14. Google ScholarDigital Library
    19. James T. Kajiya. 1986. The Rendering Equation. In ACM SIGGRAPH, Vol. 20. 143–150. Google ScholarDigital Library
    20. Jan Kautz, Pere-Pau Vázquez, Wolfgang Heidrich, and Hans-Peter Seidel. 2000. Unified Approach to Prefiltered Environment Maps. In Proceedings of the Eurographics Workshop on Rendering Techniques 2000. Springer-Verlag, London, UK, UK, 185–196. http://dl.acm.org/citation.cfm?id=647652.732274 Google ScholarCross Ref
    21. Johannes Meng, Florian Simon, Johannes Hanika, and Carsten Dachsbacher. 2015. Physically Meaningful Rendering using Tristimulus Colours. Computer Graphics Forum 34, 4 (2015), 31–40. Google ScholarDigital Library
    22. Brian E. Smits and Gary W. Meyer. 1992. Newton’s Colors: Simulating Interference Phenomena in Realistic Image Synthesis. In Photorealism in Computer Graphics. Springer, 185–194. Google ScholarCross Ref
    23. Jos Stam. 1999. Diffraction Shaders. In ACM SIGGRAPH. Google ScholarDigital Library
    24. Yinlong Sun. 2006. Rendering Biological Iridescences with RGB-based Renderers. ACM Transactions on Graphics 25, 1 (Jan. 2006), 100–129. Google ScholarDigital Library
    25. Romain Vergne and Pascal Barla. 2015. Designing Gratin, A GPU-Tailored Node-Based System. Journal of Computer Graphics Techniques (JCGT) 4, 4 (19 November 2015), 54–71. http://jcgt.org/published/0004/04/03/Google Scholar
    26. Bruce Walter, Stephen R. Marschner, Hongsong Li, and Kenneth E. Torrance. 2007. Microfacet Models for Refraction Through Rough Surfaces. In Proceedings of the 18th Eurographics Conference on Rendering Techniques (EGSR’07). Eurographics Association, Aire-la-Ville, Switzerland, Switzerland, 195–206. Google ScholarDigital Library
    27. Gregory J. Ward. 1992. Measuring and Modeling Anisotropic Reflection. SIGGRAPH Comput. Graph. 26, 2 (July 1992), 265–272. Google ScholarDigital Library
    28. Andrea Weidlich and Alexander Wilkie. 2007. Arbitrarily Layered Micro-facet Surfaces. In ACM GRAPHITE. 171–178. Google ScholarDigital Library
    29. A. Wilkie, S. Nawaz, M. Droske, A. Weidlich, and J. Hanika. 2014. Hero Wavelength Spectral Sampling. Computer Graphics Forum 33, 4 (jul 2014), 123–131. Google ScholarDigital Library
    30. Pochi Yeh. 2005. Optical Waves in Layered Media. Wiley.Google Scholar

ACM Digital Library Publication: