Presentation on theme: "Shaders Information on Light, Shadows & Roughness."— Presentation transcript:
Shaders Information on Light, Shadows & Roughness
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 Max 1. Anisotropic 2. Blinn – Ignition OK 3. Metal 4. Multi-layer 5. Oren-Nayar-Blinn 6. Phong – Ignition OK 7. Strauss 8. Translucent
Two Types of Shaders Diffuse Shaders are dominant from a surface which has small-scale roughness in the surface, with respect to wavelength, that light is reflected in many different directions from each tiny bit of the surface, with tiny changes in surface angle. Specular Shaders dominates on a surface which is smooth, with respect to wavelength. This implies that the scattered rays from each point of the surface are directed almost in the same direction, rather than being diffusely scattered. It's just a matter of the scale of the detail. If the surface roughness is much smaller than the wavelength of the incident light it appears flat and acts as a mirror.
Shaders for Ignition You may only use Blinn-Basic and Phong shading with a material you plan to directly place in Ignition. You may use other shaders if you “bake” your texture in 3DS Max. Blinn shading is the default shading in 3DS Max.
Phong Shading Phong shading smoothes the edges between faces and renders the highlights realistically for shiny, regular surfaces. Phong shaders calculate the normal for every pixel of the face. Phong shading can accurately render bump, opacity, shininess, specular, and reflection maps. The Blinn and Phong shaders have the same basic parameters.
Blinn Shading Blinn shading is a subtle variation on Phong shading. In Blinn shading, the highlights appear rounder. You may NOT use the soften parameter with materials being used directly in Ignition. With Blinn shading, you can obtain highlights produced by light glancing off the surface at low angles.
Max Shader Interface Specular Level—Affects the intensity of the specular highlight. As you increase the value, the highlight grows brighter. Default=5. Glossiness—Affects the size of the specular highlight. As you increase the value, the highlight gets smaller and the material appears shinier. Default=25. Soften — Cannot be used directly with Ignition. Highlight graph—This curve shows the effect of adjusting the values of Specular Level and Glossiness. As you decrease Glossiness, the curve grows wider; as you increase Specular Level, the curve grows taller.