Wilkie, A.Ulbricht, C.Tobler, Robert F.Zotti, G.Purgathofer, W.Alexander Keller and Henrik Wann Jensen2014-01-272014-01-2720043-905673-12-61727-3463https://doi.org/10.2312/EGWR/EGSR04/387-397Under certain circumstances the polarisation state of the illumination can have a significant influence on the appearance of scenes; outdoor scenes with specular surfaces - such as water bodies or windows - under clear, blue skies are good examples of such environments. In cases like that it can be essential to use a polarising renderer if a true prediction of nature is intended, but so far no polarising skylight models have been presented. This paper presents a plausible analytical model for the polarisation of the light emitted from a clear sky. Our approach is based on a suitable combination of several components with well-known characteristics, and yields acceptable results in considerably less time than an exhaustive simulation of the underlying atmospheric scattering phenomena would require.