Sets the Render Globals' Pre Render MEL attribute to select the currently selected items. This allows shell-initiated renders to render only active items -- selection is not saved with the Scene file and must be explicitly set with this MEL command for rendering. The Pre Render MEL attribute is saved with the scene file, so this command is not required every time you load the scene.
Select one or more items (don't forget lights, cameras and texture placements) and call this function.
Note: Calling this function more than once will append the new selection command to the Pre Render MEL attribute. This behavior is by design so as to preserve existing pre-render commands. This will still work, as the MEL command will simply replace the previous selection with the new one. Access the Render Globals via the Attribute Editor if you want to clear the command.