mental ray Architectural and Design Visualization Shader Library

70 3 Sun and Skyglow intensity=5glow intensity=0.1• physically scaled sun makes the intensity of the sun physically scaled. With asun intensity of 1.0, the sun will be as bright as it is in the real world. sun intensitycan still be used to tweak the intensity (i.e. a value of 2.0 would make a sun that is twiceas bright as the real sun). glow intensity and sun scale can still be used to tweak theaspect of the sun, but they have no impact on the total energy which is automaticallyadjusted to compensate.• sun scale sets the size of the visible sun disk. The value 1.0 is the “physically correct”size, but due to the fact that people tend to misjudge the proper size of the sun inphotographs, the default is the slightly more visually pleasing 4.0sun scale=1sun scale=4• When use background is enabled but no background has been set, the backgroundof the rendering will be transparent black, i.e. suitable for external compositing. If abackground shader is supplied, the background of the rendering will come from thatshader (for example a texture shader that looks up a background photograph of a reallocation or similar). In either case the mia physicalsky will still be visible in refractionsand reflections.3.7 CIE Sky modelThe CIE sky model is a standard model utilized in lighting analysis. It is a colorless (grayscale)model, and is hence not suitable for making ”nice images”, but it has the advantage of followinga standardized (known) luminance distribution.