Modifier

(Term used in the radiance software)

In the radiance software, every basic material can be modified in several ways. Modification can influence color, transparency, surface normals or light emission etc, depending on the type of modifier and the type of material. Modifiers can be combined, so that each modifier in the chain influences a specific property of the material.

Technically speaking, material assignment is also a modification of a surface definition.

There are several classes of modifiers:

Patterns: Patterns modify the color or light emission of a material.
Textures: Textures modify the normal vector on each point of a surface, therefore influencing the way the surface reacts to the directional components of the incident light.
Mixtures: Mixtures are a special modifier class because they don't directly modify any surface or material properties, but are used to determine the way two other modifiers or materials are blended into each other.

References:		Radiance software material

English		German
modifier		Der Modifier

Lighting Design Glossary

Modifier