...
3Delight for Maya lets you specify MEL scripts that will be executed before and/or after each Shadow Map is rendered. More precisely, the Pre/Post scripts will be executed just before the FrameBegin RIB statement and/or just after the FrameEnd RIB statement. These two attributes are empty by default. These The following variables are automatically defined in the context of the MEL scriptscripts:
string $shape_path → Contains the current light shape path.
...