ShadersShaders

Information on Light, Shadows & Information on Light, Shadows & RoughnessRoughness

What is a Shader?What is a Shader?

Shaders create the bright highlights that one would see on a glossy surface, mimicking the reflection of light sources. According to Snell's Law, light striking a specular surface will be reflected at an angle which mirrors the incident light angle (with regard to the surface's normal)

Shading in MaxShading in Max

1. Anisotropic1. Anisotropic2. Blinn – Ignition OK2. Blinn – Ignition OK3. Metal3. Metal4. Multi-layer4. Multi-layer5. Oren-Nayar-Blinn5. Oren-Nayar-Blinn6. Phong – Ignition OK6. Phong – Ignition OK7. Strauss7. Strauss8. Translucent8. Translucent

Two Types of ShadersTwo Types of Shaders

Diffuse Shaders are dominant from a surface which has Diffuse Shaders are dominant from a surface which has small-scale roughness in the surface, with respect to small-scale roughness in the surface, with respect to wavelength, that wavelength, that light is reflected in many different light is reflected in many different directions from each tiny bit of the surfacedirections from each tiny bit of the surface, with tiny , with tiny changes in surface angle. changes in surface angle. Specular Shaders dominates on a surface which is Specular Shaders dominates on a surface which is smooth, with respect to wavelength. This implies that the smooth, with respect to wavelength. This implies that the scattered rays from each point of the surface are scattered rays from each point of the surface are directed almost in the same directiondirected almost in the same direction, rather than being , rather than being diffusely scattered. It's just a matter of the scale of the diffusely scattered. It's just a matter of the scale of the detail. If the surface roughness is much smaller than the detail. If the surface roughness is much smaller than the wavelength of the incident light it appears flat and acts wavelength of the incident light it appears flat and acts as a mirror. as a mirror.

Shaders for IgnitionShaders for Ignition

You may only use Blinn-Basic and Phong You may only use Blinn-Basic and Phong shading with a material you plan to directly shading with a material you plan to directly place in Ignition. place in Ignition.

You may use other shaders if you “bake” You may use other shaders if you “bake” your texture in 3DS Max.your texture in 3DS Max.

Blinn shading is the default shading in Blinn shading is the default shading in 3DS Max.3DS Max.

Phong ShadingPhong Shading

Phong shading smoothes the Phong shading smoothes the edges between faces and renders edges between faces and renders the highlights realistically for the highlights realistically for shiny, regular surfaces.shiny, regular surfaces.Phong shaders calculate the Phong shaders calculate the normal for every pixel of the face.normal for every pixel of the face.Phong shading can accurately Phong shading can accurately render bump, opacity, shininess, render bump, opacity, shininess, specular, and reflection maps. specular, and reflection maps. The Blinn and Phong shaders The Blinn and Phong shaders have the same basic parameters.have the same basic parameters.

Blinn ShadingBlinn Shading

Blinn shading is a subtle Blinn shading is a subtle variation on Phong shading. variation on Phong shading. In Blinn shading, the highlights In Blinn shading, the highlights appear rounder.appear rounder.You may NOT use the soften You may NOT use the soften parameter with materials being parameter with materials being used directly in used directly in IgnitionIgnition..With Blinn shading, you can With Blinn shading, you can obtain highlights produced by obtain highlights produced by light glancing off the surface at light glancing off the surface at low angles. low angles.

Max Shader InterfaceMax Shader Interface

Specular Level—Specular Level—Affects the intensity of the specular Affects the intensity of the specular highlight. As you increase the value, the highlight highlight. As you increase the value, the highlight grows brighter. Default=5. grows brighter. Default=5. Glossiness—Glossiness—Affects the size of the specular Affects the size of the specular highlight. As you increase the value, the highlight highlight. As you increase the value, the highlight gets smaller and the material appears shinier. gets smaller and the material appears shinier. Default=25. Default=25. Soften — Soften — Cannot be used directly with Cannot be used directly with IgnitionIgnition..Highlight graph—Highlight graph—This curve shows the effect of This curve shows the effect of adjusting the values of Specular Level and adjusting the values of Specular Level and Glossiness. As you decrease Glossiness, the curve Glossiness. As you decrease Glossiness, the curve grows wider; as you increase Specular Level, the grows wider; as you increase Specular Level, the curve grows taller. curve grows taller.