Shader properties file used by games developed with id Tech 3, the Quake III engine; contains definitions for map textures, such as image files, scale, motion, and lighting settings; referenced by other game components, such map loaders, to set appearance properties within the game. SHADER files are stored in a plain-text format and can be viewed with a text editor. They often are located in the /scripts directory of a .PK3 game package file.