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Chapter 15: Using the Slate Material Editor

Reflection and refraction
A reflection is what you see when you look in the mirror. Shiny objects reflect their surroundings. By defin-
ing a material’s reflection values, you can control how much it reflects its surroundings. A mirror, for exam-
ple, reflects everything, but a rock won’t reflect at all.
Reflection Dimming controls how much of the original reflection is lost as the surroundings are reflected
within the scene.
Refraction is the bending of light as it moves through a transparent material. The amount of refraction that a
material produces is expressed as a value called the Index of Refraction. The Index of Refraction is the
amount that light bends as it goes through a transparent object. For example, a diamond bends light more
than a glass of water, so it has a higher Index of Refraction value. The default Index of Refraction value is
1.0 for objects that don’t bend light at all. Water has a value of 1.3, glass a value of around 1.5, and solid
crystal a value of around 2.0.
Shininess and specular highlights
Shiny objects, such as polished metal or clean windows, include highlights where the lights reflect off their
surfaces. These highlights are called specular highlights and are determined by the Specular settings. These
settings include Specular Level, Glossiness, and Soften values.
The Specular Level is a setting for the intensity of the highlight. The Glossiness determines the size of the
highlight: Higher Glossiness values result in a smaller highlight. The Soften value thins the highlight by
lowering its intensity and increasing its size.
A rough material has the opposite properties of a shiny material and almost no highlights. The Roughness
property sets how quickly the Diffuse color blends with the Ambient color. Cloth and fabric materials have
a high Roughness value; plastic and metal Roughness values are low.

Note
Specularity is one of the most important properties that we sense to determine what kind of material the object is
made from. For example, metallic objects have a specular color that is the same as their diffuse color. If the colors
are different, then the objects look like plastic instead of metal. n

Other properties
Max uses several miscellaneous properties to help define standard materials, including Diffuse Level and
Metalness.
The Diffuse Level property controls the brightness of the Diffuse color. Decreasing this value darkens the
material without affecting the specular highlights. The Metalness property controls the metallic look of the
material. Some properties are available only for certain material types.

Note
Before proceeding, you need to understand the difference between a material and a map. A material is an effect
that permeates the 3D object, but most maps are 2D images (although procedural 3D maps also exist) that can be

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