ConstReadonlydirectSun: 100000Direct midday sun.
ReadonlyfullDaylight: 20000Full daylight, not direct sun (open shade).
Readonlyovercast: 1500Overcast midday.
ReadonlysunriseSunset: 400Sunrise / sunset on a clear day.
Readonlytwilight: 10Deep twilight.
ReadonlyfullMoon: 0.25Full moon, clear night.
Reference illuminance values (lux) for directional lighting.