CS6630 Realistic Image Synthesis

Fall 2022
Location: Hollister 366
Time: M/W 9:40am-10:55am
Professor: Steve Marschner; office hours M 11:15–12:15, Th 1:00–2:00

This class covers the mathematics and physics of light transport as it pertains to the visual appearance of the world, and the algorithms and practice of using these models to generate beautiful realistic images. This includes radiometry, colorimetry, and radiative transfer; formulations of light transport in terms of recursive integrals or integral equations in path space; Monte Carlo methods for computing approximate solutions; and the craft of building fast and usable rendering software. Building on this foundation we will discuss current research topics, including differentiable rendering, and read papers from the research literature. This course is aimed at PhD students, and I'll assume reasonable maturity in math and experience building software, but it's also suitable for advanced undergraduates. It is a good way for students with some knowledge of rendering to learn the topic more deeply, or for students in neighboring fields such as computer vision, machine learning, or scientific computing to learn about the fundamentals of rendering and how the underlying problems relate to those in their own fields.

Attendance for Cornell Tech students will be supported by Zoom; please email the instructor for the link (or ask other students).

The results of the CS6630 Rendering Competition are here!


Links to non-open-access articles will work from on campus, or go to library.cornell.edu and search for an article title or DOI to get NetID authenticated access. Most articles also have author-hosted versions that can be readily discovered.

Due dates are subject to change.

date topic reading assignments
22Aug introduction to image synthesis slides    
24Aug radiometry slides notes PBR 5.4-5.6, also Preisendorfer Sec 1.1,
Nicodemus Sec. I-II
29Aug —instructor travel—    
31Aug BRDF | Monte Carlo integration slides notes PBR Ch.13 (minus warning triangle sections)
Feller on discrete and continuous random variables
5Sep —Labor Day—   A0 due 9/2
7Sep Random sampling    
12Sep Monte Carlo illumination slides notes PBR 7.2-7.4  
14Sep illumination and multiple importance sampling notebook PBR 14.1-3 (omit warning triangles),
Veach & Guibas 1995
19Sep rendering equation and path tracing slides notes PBR 14.4-5, Kayijya 1986 Illumination due 9/16
21Sep path space integrals Veach 1997 Ch. 8  
26Sep bidirectional path tracing Veach 1997 Ch. 10, Lafortune 1996  
28Sep bidirectional path tracing    
3Oct bidirectional PT | automatic differentiation slides notebook Griewank & Walther 2008  
5Oct differentiable rendering Li et al. 2018  
10Oct —Fall Break—   Ray Tracing due 10/7
12Oct differentiable rendering Loubet et al. 2019, Nimier-David et al. 2019, Zhang et al. 2019  
17Oct —instructor travel—    
19Oct —instructor travel—    
24Oct differentiable rendering    
26Oct radiative transfer notes    
31Oct volume path tracing notes   Path Tracing due 10/28
2Nov volume path tracing    
7Nov Metropolis light transport slides    
9Nov photon mapping slides    
14Nov [paper presentations] Müller et al. 2019
Reviewer: Blaire
Historian: Eric
Practitioner: Becky
16Nov [paper presentations] Kelemen et al. 2002
Reviewer: Matthew
Historian: Lingjia
Practitioner: Connor
21Nov photon mapping    
23Nov —Thanksgiving Break—    
28Nov [paper presentations] Jakob & Marschner 2012
Reviewer: Andrei
Historian: Zekun
Practitioner: Oliver
30Nov [paper presentations] Jarosz et al. 2008
Reviewer: Leul
Historian: Allison
Practitioner: Frank
5Dec [paper presentations] Chaitanya et al. 2017
Reviewer: Noah
Historian: Haotian
Practitioner: Zachary
9Dec 9:00 am rendering competition
140 Bard Hall

Problem Sets

Students will work on short problem sets due every 1–2 weeks, mainly during the first half of the semester.


During the first half of the semester students will work on a series of predefined projects to build a basic Monte Carlo rendering system in C++. During the second half of the semester students will extend their renderers to render new effects of their chosing, culminating in a rendering competition to select the technically and aesthetically best images. Assignments may be done in pairs. Projects will be graded based on reports and in-person demos.

The assignments are built in Wenzel Jakob's educational renderer, Nori, though our assignments will be somewhat different in the specifics. The details are on the CS6630 Nori page; the planned projects are:

Paper Presentations

During the second half of the semester, each student will present a paper from the rendering research literature, and read the other papers being presented.

About CS6630

Questions, help, discussion: The instructor is available to answer questions, advise on projects, or just to discuss interesting topics related to the class at office hours and by appointment as needed. For electronic communication we are using Ed Discussion (access via Canvas).

Collaboration: You are welcome (encouraged, even) to discuss projects among yourselves and to help one another track down problems. But when it comes to actually designing and implementing the projects, your code needs to be your own work (or you and your partner's). In particular, it's certainly never OK to copy parts of one person's or team's writeup, code, or results into another's, even if the general solution was worked out together.

Academic integrity: We assume the work you hand in is your own, and the results you hand in are generated by your program. You're welcome to read whatever you want to learn what you need to do the work, but we do expect you to build your own implementations of the methods we are studying. If you're ever in doubt, just include a citation in your code or report indicating where some idea came from, whether it be a classmate, a web site, another piece of software, or anything—this always maintains your honesty, whether the source was used in a good way or not. The principle is that an assignment is an academic document, like a journal article. When you turn it in, you are claiming that everything in it is your original idea (or is original to you and your partner, if you're handing in as a pair) unless you cite a source for it.

School can be stressful, and your coursework and other factors can put you under a lot of pressure, but don't let that lure you into dishonesty. If you feel you can't complete the work on your own, come talk to the professor, or your academic advisor, and we can help you figure out what to do. I want you to learn, I can be flexible about how, and you are not going to fail the class if you are putting in good effort.

For more information see Cornell's Code of Academic Integrity.


Fundamentals of Computer Graphics cover

Physically Based Rendering: From Theory to Implementation (3th ed.)

Matt Pharr, Wenzel Jakob, and Greg Humphreys

This book is an encyclopedic source for detailed implementation about the theory and practice of rendering. Its contents are available free online.

Fundamentals of Computer Graphics cover

Fundamentals of Computer Graphics (5th ed.)

Steve Marschner and Peter Shirley

This book is a good source for a lot of the basic computer graphics material, and goes at a bit gentler pace than the book above. Many of you may own a copy from CS4620. The Cornell library provides access to an electronic edition.


This is a collection references relevant to the class, some of which are assigned as reading for a particular lecture or as a paper for student presentation. Those that are assigned readings sometimes come with remarks about what part you need to read; don't forget to check that before you start!

[Appel 1968] Appel, A. “Some techniques for shading machine renderings of solids.” AFIPS ’68 (Spring): Proceedings of the April 30--May 2, 1968, spring joint computer conference, April 1968

[Arbree 2009] Arbree, A. “Scalable and Heterogeneous Rendering of Subsurface Scattering Materials.” PhD Thesis, Cornell University, August 2009

This thesis on rendering translucent materials contains a nice explanation of various boundary conditions, including a derivation of the widely used dipole approximation.

[Arvo 1995] Arvo, James. “Analytic Methods for Simulated Light Transport.” PhD Thesis, Yale University, December 1995

This thesis includes a number of mathematical methods applied to rendering; for this course the relevant parts are the excellent measure-theoretic treatment of radiometry and the operator formulation of global illumination.

[Ashikhmin & Shirley 2000] Michael Ashikhmin and Peter Shirley. “A microfacet-based BRDF generator.” SIGGRAPH 2000.

[Ben-Artzi et al. 2008] Ben-Artzi, A., Egan, K., Ramamoorthi, R., & Durand, F. “A precomputed polynomial representation for interactive BRDF editing with global illumination.” ACM Transactions on Graphics, 27(2) (2008).

[Bouthors et al. 2008] Bouthors, A., F. Neyret, N. Max, E. Bruneton, C. Crassin. “Interactive multiple anisotropic scattering in clouds.” In Proceedings of I3D 2008.

[Blinn 1977] James F. Blinn. “Models of Light Reflection for Computer Synthesized Pictures.” In Proceedings of SIGGRAPH 1977.

[Brown 1980] Gary S. Brown. “Shadowing by Non-Gaussian Random Surfaces.” IEEE Transactions on Antennas and Propagaion 28:6 (1980).

[Cerezo et al. 2005] Cerezo, Eva and Perez-Cazorla, Frederic and Pueyo, Xavier and Seron, Francisco and Sillion, Francois. "A Survey on Participating Media Rendering Techniques" in the Visual Computer. 2005

[Chaitanya et al. 2017] Chakravarty R. Alla Chaitanya, Anton S. Kaplanyan, Christoph Schied, Marco Salvi, Aaron Lefohn, Derek Nowrouzezahrai, Timo Aila. “Interactive reconstruction of Monte Carlo image sequences using a recurrent denoising autoencoder.” SIGGRAPH 2017

[Cline et al. 2005] Cline, D., Talbot, J., & Egbert, P. “Energy redistribution path tracing.” ACM Transactions on Graphics (TOG), 24(3) (2005).

[Cook & Torrance 1981] Robert L. Cook and Kenneth E. Torrence. “A Reflectance Model for Computer Graphics.” Computer Graphics. 14(3), pp. 307-316. 1981.

[Crassin et al. 2009] Crassin, C., F. Neyret, S. Lefebvre, and E. Eisenmann. “GigaVoxels: ray-guided streaming for efficient and detailed voxel rendering.” In I3D 2009.

[Debevec & Malik 1997] Debevec, P. E., AND Malik, J. Recovering high dynamic range radiance maps from photographs. In SIGGRAPH 97 (August 1997), pp. 369--378.

[Debevec et al. 2000] Paul Debevec, Tim Hawkins, Chris Tchou, Haarm-Pieter Duiker, Westley Sarokin, and Mark Sagar. “Acquiring the reflectance field of a human face” SIGGRAPH 2000.

[Drebin 1988] (acm) Drebin, R., L. Carpenter, and P. Hanrahan. “Volume rendering.” In SIGGRAPH 1988.

[d'Eon et al. 2007] d'Eon, E., D. Luebke, E. Enderton. “Efficient Rendering of Human Skin” In Eurographics Symposium on Rendering 2007.

[Feller 1968] William Feller. “Chapter IX: Random Variables; Expectation.” An Introduction to Probability Theory and Its Applications, Vol.I. 3rd Edition. John Wiley & Sons, Inc.: New York, 1968.

[Feller 1971] William Feller. “Chapter I: The Exponential and the Uniform Densities” and “Chapter III: Densities in Higher Dimensions; Normal Densities and Processes.” An Introduction to Probability Theory and Its Applications, Vol.II. 2nd Edition. John Wiley & Sons, Inc.: New York, 1971.

[Georgiev et al. 2012] Iliyan Georgiev, Jaroslav Křivánek, Tomáš Davidovič, and Philipp Slusallek. “Light transport simulation with vertex connection and merging.” SIGGRAPH 2012.

[van Ginneken et al. 1998] Bram van Ginneken, Marigo Stavridi, and Jan J. Koenderink. “Diffuse and specular reflectance from rough surfaces.” Applied Optics 37:1 (1998)

[Glassner 1995a] Andrew S. Glassner. “Chapter 12: Energy Transport.” Principles of Digital Image Synthesis. Morgan-Kaufman, 1995.

Glassner explains the volume rendering equation from the ground up, at a leisurely pace and in language familiar to graphics people.

[Glassner 1995b] Andrew S. Glassner. “Chapter 15: Shading.” Principles of Digital Image Synthesis. Morgan-Kaufman, 1995.

Glassner covers the basics of BRDFs and shading, and discusses many shading models in a fair amount of detail.

[Goesele et al. 2004] Michael Goesele, Hendrik P. A. Lensch, Jochen Lang, Christian Fuchs, Hans-Peter Seidel. “DISCO: acquisition of translucent objects.” ACM Transactions on Graphics. 23(3), pp. 835-844, 2004.

[Griewank & Walther 2008] Andreas Griewank and Andrea Walther. “Evaluating derivatives: principles and techniques of algorithmic differentiation.” SIAM Press, 2008.

[Hanrahan & Krueger 1993] Pat Hanrahan, Wolfgang Krueger. “Reflection from Layered Surfaces Due to Subsurface Scattering.” (Proceedings of SIGGRAPH 93). pp. 165-174, 1993.

[Ikits et al. 2004] Milan Ikits, Joe Kniss, Aaron Lefohn, and Charles Hansen. “Volume Rendering Techniques” In Randima Fernando, ed., GPU Gems, Pearson Education, 2004.

[Ishimaru 1978a] Akira Ishimaru. “Transport Theory of Wave Propagation in Random Particles,” Chapter 7 in Wave Propagation and Scattering in Random Media, Volume 1. Academic Press, 1978.

[Ishimaru 1978b] Akira Ishimaru. “Approximate Solutions for Tenuous Medium,” Chapter 8 in Wave Propagation and Scattering in Random Media, Volume 1. Academic Press, 1978.

[Ishimaru 1978c] Akira Ishimaru. “Diffusion Approximation,” Chapter 9 in Wave Propagation and Scattering in Random Media, Volume 1. Academic Press, 1978.

[Jakob et al. 2010] Wenzel Jakob, Adam Arbree, Jonathan T. Moon, Kavita Bala, and Steve Marschner. “A Radiative Transfer Framework for Rendering Materials with Anisotropic Structure” SIGGRAPH 2010.

This paper's main topic is light transport in anisotropic materials, but the accompanying tech report contains nice derivations of the standard case as well, for the diffusion approximation and the dipole BSSRDF.

[Jakob & Marschner 2012] Wenzel Jakob and Steve Marschner. “Manifold exploration: a Markov Chain Monte Carlo technique for rendering scenes with difficult specular transport.” SIGGRAPH 2012.

[Jarosz et al. 2008] Wojciech Jarosz, Matthias Zwicker, and Henrik Wann Jensen. “The Beam Radiance Estimate for Volumetric Photon Mapping.” EUROGRAPHICS 2008.

[Jensen 1996] Jensen, H. W. Global illumination using photon maps. In Rendering Techniques '96, pages 21--30, 1996

[Jensen & Christensen 1998] Henrik W. Jensen and Per H. Christensen. “Efficient Simulation of Light Transport in Scene with Participating Media using Photon Maps.”(Proceedings of SIGGRAPH 98). pp. 311-320, 1998.

[Jensen et all. 2001] Henrik Wann Jensen, Stephen R. Marschner, Marc Levoy, Pat Hanrahan. “A Practical Model for Subsurface Light Transport.” (Proceedings of ACM SIGGRAPH 2001). pp. 511-518, 2001.

[Jensen & Buhler 2002] Henrik Wann Jensen and Juan Buhler. “A Rapid Hierarchical Rendering Technique for Translucent Materials.” In SIGGRAPH 2002.

[Kajiya 1986] James T. Kajiya. “The Rendering Equation.” Computer Graphics (Proceedings of SIGGRAPH 86). 20(4), pp. 143-150, 1986.

This seminal work on light transport for graphics formalizes rendering using the Rendering Equation, which we now take as the theoretical basis for rendering of surfaces.

[Kajiya & von Herzen] J. Kajiya and B. Von Herzen, “Ray tracing volume densities.” SIGGRAPH 1984, July 1984, pp. 165-174.

[Kelemen 2002] Csaba Kelemen, László Szirmay-Kalos, György Antal, and Ferenc Csonka, “A Simple and Robust Mutation Strategy for the Metropolis Light Transport Algorithm.” Computer Grapics Forum 21:3, September 2002.

[Keller 1997] Keller, A. “Instant radiosity.” SIGGRAPH 1990.

[Kindlmann & Durkin 1998] Kindlmann, G., and J. W. Durkin. “Semi-Automatic Generation of Transfer Functions for Direct Volume Rendering.” In IEEE Symposium on Volume Visualization 1998.

[Koenderink et al. 1999] Koenderink, J.J., A.J. van Doorn, K.J. Dana, and S. Nayar. “Bidirectional Reflection Distribution Function of Thoroughly Pitted Surfaces.” International Journal of Computer Vision 31 (1999).

[Kniss et al. 2002] Kniss, J., G. Kindlmann, and C. Hansen. “Multidimensional Transfer Functions for Interactive Volume Rendering.” IEEE TVCG 8:3 (2002).

[Kniss et al. 2003] Kniss, J., S. Premoze, C. Hansen, and P. Shirley. “A model for volume lighting and modeling.” IEEE TVCG 9:2 (2003).

[Křivánek et al. 2014] Jaroslav Křivánek, Iliyan Georgiev, Toshiya Hachisuka, Petr Vévoda, Martin Šik, Derek Nowrouzezahrai, and Wojciech Jarosz. “Unifying points, beams, and paths in volumetric light transport simulation.” SIGGRAPH 2014.

[Lacroute & Levoy 1994] Lacroute, P. and M. Levoy. “Fast Volume Rendering Using a Shear-Warp Factorization of the Viewing Transformation.” In SIGGRAPH 1994.

[Lafortune 1996] Lafortune, Eric. “Mathematical Models and Monte Carlo Algorithms for Physically Based Rendering.” PhD Thesis, Katholieke Universiteit Leuven, February 1996.

This thesis introduces bidirectional path tracing (see also Veach & Guibas), and also contains nice explanations of all the radiometric and probabilistic ideas leading up to it.

[Lehtinen et al. 2011] Lehtinen, J., Aila, T., Chen, J., Laine, S., Durand, F., Lehtinen, J., et al. “Temporal light field reconstruction for rendering distribution effects.” SIGGRAPH 2011.

[Lehtinen et al. 2012] Lehtinen, J., Aila, T., Laine, S., & Durand, F. “Reconstructing the indirect light field for global illumination.” SIGGRAPH 2012.

[Lehtinen et al. 2013] Lehtinen, J., Karras, T., Laine, S., Aittala, M., Durand, F., & Aila, T. “Gradient-domain metropolis light transport.” ACM Transactions on Graphics, 32(4) (2013).

[Lensch et all. 2003] Hendrik P. A. Lensch, Jan Kautz, Michael Goesele, Wolfgang Heidrich, Hans-Peter Seidel. “Image-based reconstruction of spatial appearance and geometric detail.” ACM Transactions on Graphics. 22(2), pp. 234-257, 2003.

[Levoy 1988] Levoy, M. “Display of surfaces from Volume Data.” IEEE Computer Graphics & Applications 8:3 (1988).

[Li et al. 2018] Tzu-Mao Li, Miika Aittala, Frédo Durand, and Jaakko Lehtinen. “Differentiable Monte Carlo Ray Tracing through Edge Sampling.” SIGGRAPH Asia 2018.

[Loubet et al. 2019] Guillaume Loubet, Nicolas Holzschuch, and Wenzel Jakob. “Reparameterizing discontinuous integrands for differentiable rendering.” SIGGRAPH Asia 2019.

[Matusik et al. 2003] Wociech Matusik, Hanspeter Pfister, Matt Brand, and Leonard McMillan, “A data-driven reflectance model,” SIGGRAPH 2003. [author page]

[Mitsunaga & Nayar 1999] Mitsunaga and S. K. Nayar. Radiometric self calibration. In Proc CVPR, volume 2, pages 374--380, June 1999

[Müller et al. 2019] Thomas Müller, Brian Mcwilliams, Fabrice Rousselle, Markus Gross, and Jan Novák. “Neural Importance Sampling.” ACM Transactions on Graphics 38:5, October 2019.

[Nicodemus et al. 1977] F.E. Nicodemus, J.C. Richmond, J.J. Hsia, I.W. Ginsberg, and T. Limperis. Geometrical Considerations and Nomenclature for Reflectance. National Bureau of Standards (U.S.) monograph, issued October 1977.

This monograph is the origin of the terminology and (nearly) the notation that we use for surface reflection in graphics, including the BRDF and the BSSRDF. Sections I and II are the most relevant for rendering; Section IV is required reading for anyone who is going to measure light reflection.

[Nimer-David et al. 2019] Merlin Nimier-David, Delio Vicini, Tizian Zeltner, and Wenzel Jakob. “Mitsuba 2: a retargetable forward and inverse renderer.” SIGGRAPH Asia 2019.

[Ngan et al. 2005] Ngan, A., Durand, F., & Matusik, W. “Experimental analysis of BRDF models.” Proceedings of the 2005 Eurographics Symposium on Rendering. [author page]

[Novak et al. 2012] Jan Novák, Derek Nowrouzezahrai, Carsten Dachsbacher, and Wojciech Jarosz. “Virtual ray lights for rendering scenes with participating media,” SIGGRAPH 2012.

[Oren & Nayar 1995] Michael Oren and Shree K. Nayar. “Generalization of the Lambertian Model and Implications for Machine Vision” International Journal of Computer Vision 14:3 (1995).

[Poulin & Fournier 1990] Pierre Poulin and Alain Fournier. “A model for anisotropic reflection,” SIGGRAPH 1990.

[Preisendorfer 1976] Rudolph W. Preisendorfer. Hydrologic Optics, Vol. I. Section 1.1.

This section provides clear, operational definitions of all the important radiometric quantities. When you read it for class, feel free to skim over the parts that are specific to the hydrologic context.

The rest of Preisendorfer's book contains similarly clear explanations of many of the classical radiative transfer results we have borrowed for graphics.

[Premoze et al. 2004] Simon Premoze, Michael Ashikhmin, Jerry Tessendorf, Ravi Ramamoorthi, Shree Nayar. “Practical Rendering of Multiple Scattering Effects in Participating Media.” Rendering Techniques 2004: 15th Eurographics Workshop on Rendering. pp. 363-374, 2004.

[Sadeghi et al. 2012] Sadeghi, I., Munoz, A., Laven, P., Jarosz, W., Seron, F., Gutierrez, D., & Jensen, H. W. “Physically-based simulation of rainbows.” ACM Transactions on Graphics, 31(1), (2012).

[Shirley et al. 1996] Peter Shirley, Changyaw Wang, Kurt Zimmerman. “Monte Carlo Techniques for Direct Lighting Calculations.” ACM Transactions on Graphics. 15(1), pp. 1-36, 1996.

This paper discusses the details of choosing random shadow rays to sample planar or spherical luminaires.

[Smith 1967] Bruce G. Smith. “Geometrical Shadowing of a Random Rough Surface.” IEEE Transactions on Antennas and Propagation 15:5 (1967)

[Szeliski & Shum 1997] R. Szeliski and H. Shum. “Creating full view panoramic image mosaics and environment maps.” In Proc. of SIGGRAPH, pages 251–258, 1997

[Torrance & Sparrow 1967] K.E. Torrance and E.M. Sparrow. “Theory for Off-specular Reflection from Roughened Surfaces.” Journal of the Optical Society of America 57:9 (1967).

[Veach & Guibas 1994] Eric Veach and Leonidas J. Guibas. “Bidirectional Estimators for Light Transport” (Proceedings of EGRW 1994). 1995.

[Veach & Guibas 1995] Eric Veach and Leonidas J. Guibas. “Optimally Combining Sampling Techniques for Monte Carlo Rendering” (Proceedings of SIGGRAPH 95). pp. 419-428, 1995.

[Veach & Guibas 1997] Veach, E., & Guibas, L. “Metropolis light transport.” SIGGRAPH 1997.

[Veach 1997] Eric Veach. “Robust Monte Carlo Methods for Light Transport Simulation.” PhD Thesis, Stanford University, December 1997.

This thesis introduces a number of important Monte Carlo rendering methods, including multiple importance sampling, bidirectional path tracing (see also Lafortune & Willems), and Metropolis Light Transport.

[Walter et al. 2005] Walter, B., Fernandez, S., Arbree, A., Bala, K., Donikian, M., Greenberg, D. P., et al. “Lightcuts: a scalable approach to illumination.” ACM Transactions on Graphics, 24(3) (2005).

[Walter et al. 2007] Bruce Walter, Stephen R. Marschner, Hongsong Li, and Kenneth E. Torrance. “Microfacet Models for Refraction through Rough Surfaces.” Eurographics Symposium on Rendering 2007.

The slides I presented in class came originally from the presentation of this paper. The notation and presentation of the microfacet framework is similar, though you won't see the delta functions that appear in the paper in class.

[Walter et al. 2009] Walter, B., Zhao, S., Holzschuch, N., & Bala, K. “Single scattering in refractive media with triangle mesh boundaries.” ACM Transactions on Graphics, 28(3) (2009).

[Whitted 1980] Whitted, T. “An improved illumination model for shaded display.” Communications of the ACM 23:6, June 1980

[Wyman et al. 2006] Chris Wyman, Steven Parker, Peter Shirley, and Charles Hansen. “Interactive display of isosurfaces with global illumination.” IEEE TVCG 12:2 (2006).

[Xu et al. 2001] Xu, Y-Q., Chen, Y., Lin, S., Zhong, H., Wu, E., Guo, B., and Shum, H-Y. “Photorealistic rendering of knitwear using the Lumislice.” In SIGGRAPH 2001.

[Zhang et al. 2019] Cheng Zhang, Lifan Wu, Changxi Zheng, Ioannis Gkioulekas, Ravi Ramamoorthi, and Shuang Zhao. “A differential theory of radiative transfer.” SIGGRAPH Asia 2019.

[Zhao et al. 2011] Shuang Zhao, Wenzel Jakob, Steve Marschner, and Kavita Bala. “Building Volumetric Appearance Models of Fabric using Micro CT Imaging,” ACM Transactions on Graphics (SIGGRAPH 2011), 30(4), July 2011.

[Zhao et al. 2012] Shuang Zhao, Wenzel Jakob, Steve Marschner, and Kavita Bala. “Structure-aware Synthesis for Predictive Woven Fabric Appearance,” ACM Transactions on Graphics (SIGGRAPH 2012), 31(4), July 2012