mental ray Architectural and Design Visualization Shader Library

2.6 Tips and Tricks 59Many small adjacent cylindersAs one can see, the specular highlight in each of the cylinders work together to create anaggregate effect which is the anisotropic highlight.Also note that the highlight isn’t continuous, it is actually broken up in small adjacentsegments. I.e. the main visual cues that a material is “brushed metal’ are:• Anisotropic highlights that stretch out in a direction perpendicular to the brushingdirection.• A discontinuous highlight with “breaks” in the brushing direction.Many attempts to simulate brushed metals have only looked at the first effect, the anisotropy.Another common mistake is to think that the highlight stretches in the brushing direction.Neither is true.Hence, to simulate brushed metals, we need to simulate these two visual cues. The first one issimple; use anisotropy and anisotropy rotationto make anisotropic highlights. The secondcan be done in several ways:• With a bump map• With a map that varies the anisotropy or refl gloss• With a map that varies the refl color