Script Variable is a script variable defined to represent scene objects. One script variable points toward one scene object. You can change the 3d scene by operating script variables in script codes. To define a script variable, select an object in scene, then right-click, choose "Define Script Variable..." on the popup menu that appears. Textures, materials, lights, and mobiles can all be defined to script variables. For singleton objects, their script variable is predefined ( scene, camera, draw, etc ).