Homeworld Effects Manual: setLighting()
setLighting(int flag)
Determines whether object is affected by directional lights.
Legal values: integers
Default value: 0
If flag is 0, the object is not affected by the directional lights in the level. Otherwise, lights affect the object.
Explosions and magic usually don't care about the local light conditions, so setLighting(0) is great for such effects. However, if you want to make an effect that looks like a physical object, like a ship exitting hyperspace, then setLighting(1) makes the effect look more convincing. Include setIllum(1) and the light will fall on your object exactly as it does on a real ship.