Light
Lighting is a class of objects lighting up a room, or a part of an outdoor area.
The outdoors receive daylight during daytime. Light spreads into rooms through windows, window-doors, walls and half-walls.
Lighting fixtures are automatic by default: they are turned on, if there are any Sims awake in the room. If all Sims leave the room, or fall asleep, the lights turn off. The player can also turn them on or off.
Lack of lighting in a room, or a location outdoors, damages Sims mood; through Room motive (The Sims), Environment motive (The Sims 2), or the It's Dark moodlet (The Sims 3).
Some creatures, such as Vampires, need no lighting.