Efficient surface diffraction renderings with Chebyshev approximations
SIGGRAPH ASIA 2016 Technical Briefs on - SA '16
L = 2 L = 3 L = 25 L = 67 Our method Lab photo Benchmark method [Dhillon et al. 2014] Figure 1: Diffraction pattern seen on a screen due to a beam incident on a gold plated Sunbeam snakeskin patch (setup and lab photo from [Dhillon et al. 2014]). Rendering with our proposed method (left) qualitatively well matches the photograph (center left) with just two lookup tables including reproducing the characteristic asymmetry in the diffraction lobes. In comparison, Dhillon et al.'s method (right)
... s method (right) requires a large number of tables for accurate rendering. Abstract We propose an efficient method for reproducing diffraction colours on natural surfaces with complex nanostructures that can be represented as height-fields. Our method employs Chebyshev approximations to accurately model view-dependent iridescences for such a surface into its spectral bidirectional reflectance distribution function (BRDF). As main contribution, our method significantly reduces the runtime memory footprint from precomputed lookup tables without compromising photorealism. Our accuracy is comparable with current state-of-the-art methods and better at equal memory usage. Furthermore, a Chebyshev polynomial basis set with its near-best approximation properties allow for scalable memory-vs-performance trade-offs. We show realistic diffraction effects with just two lookup textures for natural, quasi-periodic surface nanostructures. Performance intensive applications like games and VR can benefit from our method, especially for low-end GPU or mobile platforms.