Material

(Term used in the Radiance software)

In Radiance, materials define the basic properties of every surface.

There are several classes of materials:

• Plastic like materials are opaque and can have diffuse and specular reflection properties. Specularly reflected light keeps the color of the light source.
• Metal like materials are similar to plastic, but specularly reflected light takes material color.
• Transparent materials can have specular and diffuse reflecion as well as transmission properties.
• Glass and glass like materials specularly transmit and reflect light and also have refractive properties.
• BRTDs, Bidirectional Reflection and Transmission Descriptions are the most general "material" type. All reflective and transmissive properties can be controlled exactly for light entering and exiting in any direction.
• Mist is used to model voluminous participating media like smoke, fog or "muddy water".
• There are some other specialised material types to model prismatic glazings for light redirection.
• Most material types exist in varieties that allow for anisotropic definition of their properties, or that can take be influenced from functions or data files.
• Antimatter is a special "material" type, which subtracts from other materials. This works best when applied to objects of simple shape and closed volume, which intersect with other objects.

Radiance allows modifiers to be applied to all materials that can influence the color, manipulate the normal vector of the surface or blend two materials or modifiers into each other with a defined function.