1997 | OriginalPaper | Buchkapitel
Plane-Parallel Radiance Transport for Global Illumination in Vegetation
verfasst von : Nelson Max, Brett Keating, Curtis Mobley, En-Hua Wu
Erschienen in: Rendering Techniques ’97
Verlag: Springer Vienna
Enthalten in: Professional Book Archive
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This paper applies plane-parallel radiance transport techniques to scattering from vegetation. The leaves, stems, and branches are represented as a volume density of scattering surfaces, depending only on height and the vertical component of the surface normal. Ordinary differential equations are written for the multiply scattered radiance as a function of the height above the ground, with the sky radiance and ground reflectance as boundary conditions. They are solved using a two-pass integration scheme to unify the two-point boundary conditions, and Fourier series for the dependence on the azimuthal angle. The resulting radiance distribution is used to precompute diffuse and specular “ambient” shading tables, as a function of height and surface normal, to be used in rendering, together with a z-buffer shadow algorithm for direct solar illumination.