“Interactive hair rendering under environment lighting” by Ren, Zhou, Li, Hua and Guo

  • ©Zhong Ren, Kun Zhou, Tengfei Li, Wei Hua, and Baining Guo

Conference:


Type:


Title:

    Interactive hair rendering under environment lighting

Presenter(s)/Author(s):



Abstract:


    We present an algorithm for interactive hair rendering with both single and multiple scattering effects under complex environment lighting. The outgoing radiance due to single scattering is determined by the integral of the product of the environment lighting, the scattering function, and the transmittance that accounts for self-shadowing among hair fibers. We approximate the environment light by a set of spherical radial basis functions (SRBFs) and thus convert the outgoing radiance integral into the sum of radiance contributions of all SRBF lights. For each SRBF light, we factor out the effective transmittance to represent the radiance integral as the product of two terms: the transmittance and the convolution of the SRBF light and the scattering function. Observing that the convolution term is independent of the hair geometry, we precompute it for commonly-used scattering models, and reduce the run-time computation to table lookups. We further propose a technique, called the convolution optical depth map, to efficiently approximate the effective transmittance by filtering the optical depth maps generated at the center of the SRBF using a depth-dependent kernel. As for the multiple scattering computation, we handle SRBF lights by using similar factorization and precomputation schemes, and adopt sparse sampling and interpolation to speed up the computation. Compared to off-line algorithms, our algorithm can generate images of comparable quality, but at interactive frame rates.

References:


    1. Agarwal, S., Ramamoorthi, R., Belongie, S., and Jensen, H. W. 2003. Structured importance sampling of environment maps. ACM Trans. Graph. 22, 3, 605–612. Google ScholarDigital Library
    2. Annen, T., Dong, Z., Mertens, T., Bekaert, P., Seidel, H.-P., and Kautz, J. 2008. Real-time, all-frequency shadows in dynamic scenes. ACM Trans. Graph. 27, 3, 34:1–8. Google ScholarDigital Library
    3. Cook, R. L., Halstead, J., Planck, M., and Ryu, D. 2007. Stochastic simplification of aggregate detail. ACM Trans. Graph. 26, 3, 79. Google ScholarDigital Library
    4. Fernando, R. 2005. Percentage-closer soft shadows. In SIGGRAPH 2005 Sketches, 35. Google ScholarDigital Library
    5. Harris, M., Sengupta, S., and Owens, J. 2007. Parallel prefix sum (scan) in CUDA. GPU Gems 3, Chapter 39.Google Scholar
    6. Hensley, J., Scheuermann, T., Coombe, G., Singh, M., and Lastra, A. 2005. Fast summed-area table generation and its applications. Computer Graphics Forum, 547–555.Google Scholar
    7. Kajiya, J. T., and Kay, T. L. 1989. Rendering fur with three dimensional textures. In Proceedings of ACM SIGGRAPH9, 271–280. Google ScholarDigital Library
    8. Kim, T.-Y., and Neumann, U. 2001. Opacity shadow maps. In Eurographics Workshop on Rendering, 177–182. Google ScholarDigital Library
    9. Lokovic, T., and Veach, E. 2000. Deep shadow maps. In Proceedings of ACM SIGGRAPH, 385–392. Google ScholarDigital Library
    10. Marschner, S. R., Jensen, H. W., Cammarano, M., Worley, S., and Hanrahan, P. 2003. Light scattering from human hair fibers. ACM Trans. Graph. 22, 3, 780–791. Google ScholarDigital Library
    11. Mertens, T., Kautz, J., Bekaert, P., and Reeth, F. V. 2004. A self-shadow algorithm for dynamic hair using density clustering. In SIGGRAPH 2004 Sketches, 44. Google ScholarDigital Library
    12. Moon, J. T., and Marschner, S. R. 2006. Simulating multiple scattering in hair using a photon mapping approach. ACM Trans. Graph. 25, 3, 1067–1074. Google ScholarDigital Library
    13. Moon, J. T., Walter, B., and Marschner, S. 2008. Efficient multiple scattering in hair using spherical harmonics. ACM Trans. Graph. 27, 3, 31:1–7. Google ScholarDigital Library
    14. Ng, R., Ramamoorthi, R., and Hanrahan, P. 2003. Allfrequency shadows using non-linear wavelet lighting approximation. ACM Trans. Graph. 22, 3, 376–381. Google ScholarDigital Library
    15. NVIDIA, 2007. CUDA homepage. http://developer.nvidia.com/object/cuda.html.Google Scholar
    16. Ramamoorthi, R., and Hanrahan, P. 2001. An efficient representation for irradiance environment maps. In Proceedings of ACM SIGGRAPH, 497–500. Google ScholarDigital Library
    17. Sintorn, E., and Assarsson, U. 2008. Real-time approximate sorting for self shadowing and transparency in hair rendering. In Proceedings of I3D, 157–162. Google ScholarDigital Library
    18. Sintorn, E., and Assarsson, U. 2009. Hair self shadowing and transparency depth ordering using occupancy maps. In Proceedings of I3D, 67–74. Google ScholarDigital Library
    19. Sloan, P.-P., Kautz, J., and Snyder, J. 2002. Precomputed radiance transfer for real-time rendering in dynamic, low-frequency lighting environments. In Proceedings of ACM SIGGRAPH, 527–536. Google ScholarDigital Library
    20. Tsai, Y.-T., and Shih, Z.-C. 2006. All-frequency precomputed radiance transfer using spherical radial basis functions and clustered tensor approximation. ACM Trans. Graph. 25, 3, 967–976. Google ScholarDigital Library
    21. Ward, K., Bertails, F., Kim, T.-Y., Marschner, S. R., Cani, M.-P., and Lin, M. 2007. A survey on hair modeling: Styling, simulation, and rendering. IEEE Transactions on Visualization and Computer Graphics (TVCG) 13, 2, 213–234. Google ScholarDigital Library
    22. Yuksel, C., and Keyser, J. 2008. Deep opacity maps. Computer Graphics Forum 27, 2, 675–680.Google ScholarCross Ref
    23. Zinke, A., and Weber, A. 2007. Light scattering from filaments. IEEE Trans. Vis. Comp. Graph. 13, 2, 342–356. Google ScholarDigital Library
    24. Zinke, A., Yuksel, C., Weber, A., and Keyser, J. 2008. Dual scattering approximation for fast multiple scattering in hair. ACM Trans. Graph. 27, 3, 32:1–10. Google ScholarDigital Library
    25. Zinke, A. 2008. Photo-Realistic Rendering of Fiber Assemblies. PhD thesis, University of Bonn.Google Scholar


ACM Digital Library Publication: