sd_dynamic_rooms and sd_dynamic_exit allows a builder to create one area as a template. Then, just by naming the door and attaching the first script, it will load predefined objects into the room, and delete them when the player exits. It basically allows an infinite amount of areas to be created in the one area. The idea was to make the multiple houses in a town easier to use, but still able to have different characters and objects in the house without creating 10 or 20 areas.