Separable Subsurface Scattering

Autor: Károly Zsolnai, Thomas Auzinger, Diego Gutierrez, Christian Freude, Adrian Jarabo, Michael Wimmer, Xian-Chun Wu, Javier von der Pahlen, Jorge Jimenez
Rok vydání: 2015
Předmět:
Zdroj: Computer Graphics Forum. 34:188-197
ISSN: 0167-7055
DOI: 10.1111/cgf.12529
Popis: In this paper, we propose two real-time models for simulating subsurface scattering for a large variety of translucent materials, which need under 0.5 ms per frame to execute. This makes them a practical option for real-time production scenarios. Current state-of-the-art, real-time approaches simulate subsurface light transport by approximating the radially symmetric non-separable diffusion kernel with a sum of separable Gaussians, which requires multiple up to 12 1D convolutions. In this work we relax the requirement of radial symmetry to approximate a 2D diffuse reflectance profile by a single separable kernel. We first show that low-rank approximations based on matrix factorization outperform previous approaches, but they still need several passes to get good results. To solve this, we present two different separable models: the first one yields a high-quality diffusion simulation, while the second one offers an attractive trade-off between physical accuracy and artistic control. Both allow rendering of subsurface scattering using only two 1D convolutions, reducing both execution time and memory consumption, while delivering results comparable to techniques with higher cost. Using our importance-sampling and jittering strategies, only seven samples per pixel are required. Our methods can be implemented as simple post-processing steps without intrusive changes to existing rendering pipelines.
Databáze: OpenAIRE
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