Physical Sky

Redshift supports a Physical Sky environment shader based on the PRG Clear Sky model from the paper "A Fitted Radiance and Attenuation Model for Realistic Atmospheres" which improves upon the Hosek-Wilkie sky model. PRG Clear Sky is able to better represent scenarios where the sun is very near or below the horizon, allowing for much more accurate and aesthetically pleasing sunrises and sunsets.

The Physical Sky environment shader can be used on its own or connected with a Physical Sun directional light that exhibits the same coloration and intensity behavior in order to create very realistic sunlit scenes.