Title: Real-time rendering of colour-shift effect of metallic materials

Authors: R.P.C. Janaka Rajapakse, Kazunori Miyata, Ashu Marasinghe, Yoshimasa Tokuyama

Addresses: Center for Hyper Media Research, Graduate School of Engineering, Tokyo Polytechnic University, 1583 Iiyama, Atsugi, Kanagawa 243-0297, Japan. ' Center for Knowledge Science, School of Knowledge Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan. ' Department of Management and Information Systems, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188, Japan. ' Department of Media and Image Technology, Faculty of Engineering, Tokyo Polytechnic University, 1583 Iiyama, Atsugi, Kanagawa 243-0297, Japan

Abstract: The directional-dependent effects of the materials are responsible for our perception of certain materials being realistic or not. Some materials consist of colour pigments, and these cause directional-dependent colour variations (or colour-shifts). For instance, we can observe a colour-shift effect of metallic materials, which means the changing of colour from metallic colour to pigment colour depending on the direction of incident illumination and direction of view. The most common criticism of existing analytical Bidirectional Reflectance Distribution Function (BRDF) models is that these models are inadequate to generate colour-shift effect of materials for realistic real-time rendering. This paper introduces a visually plausible shading model to generate colour-shift effect of metallic materials by modifying specular component with illumination and view dependent sheen. The developed shaders have intuitive parameters, which can generate different kinds of metallic effects for real-time rendering, including visually plausible gold, brass, silver, bronze and copper effects for real-time rendering.

Keywords: colour shift effect; metallic materials; shading models; real-time rendering; shaders; colour variations; incident illumination; view direction; gold effects; brass effects; silver effects; bronze effects; copper effects.

DOI: 10.1504/IJBM.2010.031797

International Journal of Biometrics, 2010 Vol.2 No.2, pp.185 - 200

Published online: 24 Feb 2010 *

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