mental ray Architectural and Design Visualization Shader Library

110 5 General Utility ShadersKeep in mind that other objects will still reflect in the traditional manner with multiplesamples, and this feature only applies to environment lookups. Therefore it can be veryadvantageous to use refl falloff dist to limit “actual” reflections to nearby objects only, andlet the environment take over for distant objects 3 :No refl falloff distrefl falloff dist usedIn the right image the legs of the horse only reflect very near to the floor, and conversely thehorse only reflects the very nearest parts of the floor - the rest is environment reflections. Thisyields a faster result than actually tracing those reflections, and cuts down on the noise in theimage.5.3 Light Surface5.3.1 Shader Functionality and ParametersThe mia light surface shader is primarily intended to help creating physically plausible rendersof the “visible” portion of a light source - the actual tube in a fluorescent tube, the actualbulb in a light bulb, etc. while still using a traditional CG “light” to create the illuminationof the scene (see the use cases described below).3 This is particularly true in a visual effects context.