This provides for renderings which can be created very quickly and easily, and which can be very realistic looking, although they are generally not entirely accurate in the finer details of lighting effects. In a full lighting simulation such as provided by Radiance, the optical properties are taken fully into account for both direct and diffusely reflected light, providing for the ultimate in realism and accuracy of even subtle and complex lighting conditions. The challenge to using this ultimate technology is working with a more complex project definition, including complex material types, and understanding the real physical properties of materials that underlay each material type. Material Types Radiance materials come in several basic predefined types, and applying and extending these types is a large part of the art of creating a realistic architectural simulation. Each material type uses a specific set of parameters.
Direction is output direction, in three components.
Transmissivity is the fraction of light that gets through the material. Other material types, used more rarely, include illum, dielectric, interface, and antimatter. See the main Radiance site materials overview for details. Pattern and Texture Patterns and textures are modifiers for the basic Radiance materials. Textures vary the apparent local shape of a surface by perturbing the surface normal across the object surface, which causes shading variations perceived as bumps, waves, etc.