Spectral Rendering with Daylight: A Comparison of Two Spectral Daylight Simulation Platforms
Priji Balakrishnan, Alstan J.Jakubiec
Abstract
Colours that surround us are not just the result of surface properties, rather the interplay between the spectral distribution of illuminating light and spectrally specific surface reflectance. Despite the temporal and spatial variation of daylight spectral distribution, daylight simulation platforms most commonly use luminance based sky models (CIE or all-weather Perez skies) that lack spectral and colorimetric information. LARK and ALFA are the two currently available spectral daylight simulation platforms that use spectral data of skies and materials to produce daylight renderings. The authors measure and perform visual, spectral and colour difference comparisons of complex urban scenes with different materiality|plaster facades, vegetation, reflective facades|in LARK, ALFA and standard non-spectral daylight simulations. The comparisons present the challenges, applications and limitations of using the currently evolving multi-spectral daylight simulations.