mental ray Architectural and Design Visualization Shader Library

2.6 Tips and Tricks 57Enjoy the tropics2.6.2.8 MetalsMetals are very reflective, which means they need something to reflect. The best lookingmetals come from having a true HDRI environment, either from a spherically mapped HDRIphoto 16 , or something like the mental ray physical sky.To set up classic chrome, turn brdf fresnel off, set reflectivity to 1.0, brdf 0 degree reflto 0.9 and brdf 90 degree refl to 1.0. Set diffuse to white and check the refl is metalcheckbox.This creates an almost completely reflective material. Tweak the refl gloss parameter forvarious levels of blurry reflections to taste. Also consider using the “round corners” effect,which tend to work very well on metallic objects.Metals also influence the color of their reflections. Since we enabled refl is metal this isalready happening; try setting the diffuse to a “gold” color to create gold.Try various levels of refl gloss (with the help of refl interpolate for performance, whennecessary).One can also change the reflectivity which has a slightly different meaning whenrefl is metal is enabled; it blends between the reflections (colored by the diffuse) and normaldiffuse shading. This allows a “blend” between the glossy reflections and the diffuse shading,both driven by the same color. For example, an aluminum material would need a bit of diffuseblended in, whereas chrome would not.16 Many HDRI images are available online.