mental ray Architectural and Design Visualization Shader Library

Chapter 3Sun and Sky3.1 IntroductionThe mental ray physical sun & sky shaders are designed to enable physically plausible daylightsimulations and very accurate renderings of daylight scenarios.3.1.1 Analysis useThe shader library provides tools for lighting analysis. A shader for the standard CIE skymodel (both clear and overcast) is available. This shader is grayscale (no color) and intendedfor analysis purposes rather than generating visually pleasing images. See page 70 for details.The mia physicalsky shader supports analysis related parameters from the Perez sky model,as well as explicit illuminance parameter for the mia physicalsun.3.1.2 General overviewThe mia physicalsun and mia physicalsky are intended to be used together, with themia physicalsun shader applied to a directional light that represents the sun light, and themia physicalsky shader used as the scenes camera environment shader. The environmentshader should be used to illuminate the scene with the help of Final Gathering (which mustbe enabled) and bounced light from the sun can be handled either by final gather diffusebounces, or via GI (photons).For improving quality in indoor shots, the sky can be combined with the mia portal lightshader described on page 71.