Autodesk 12812-051462-9011 User Guide 3 - Page 278

at 0.0, the material is completely opaque; at 100.0, the material is as translucent as possible. The amount spinner for a translucency map scales the map. If no map is assigned, the spinner value is used by itself. Index of Refraction The index of refraction (IOR) controls how severely the material refracts transmitted light, and how reflective the material appears. At 1.0, the IOR of air, the object behind the transparent object does not distort. At 1.5, the object behind distorts greatly, like a glass marble. Range=1.0 to 2.5. Common IORs (assuming the camera is in air or a vacuum) are: Material IOR Value Vacuum 1.0 (exactly) Air 1.0003 Water 1.333 Glass 1.5 to 1.7 Diamond 2.419 In the physical world, the IOR results from the relative speeds of light through the transparent material and the medium the eye or the camera is in. Typically this is related to the object's density: the higher the IOR, the denser the object. The IOR affects how shiny a material appears; or, in the case of transparent materials such as water or glass, the amount of distortion. For nontransparent materials, the higher the IOR, the more light is reflected from the material, and the shinier the material appears. A refractive index of 1.0 means that all light is transmitted into the material. In this case, even if the material has a high Shininess value, the surface appears perfectly diffuse, and shows no specular highlights. Luminance cd/m2 When its luminance is greater than 0.0, the material appears to glow, and if you turn on Emit Energy (see below), it contributes energy to the radiosity solution on page 6168. Luminance is measured in candelas per meter squared. The amount spinner for a luminance map scales the map. If no map is assigned, the spinner value is used by itself. Architectural Material | 5533