The Linear Parameters are located in a linear light’s Control Window (see Use the Control Window).
Controls how quickly light intensity decreases with distance. The Decay setting has no effect at distances less than 1 unit.
The Decay parameter works differently for volume lights (see Decay). Valid settings are 0, 1, 2 or 3. The default setting is 1.
0 | no decay; light reaches everything |
1 | light intensity decreases directly (linearly) with distance (slower than real world light) |
2 | light intensity decreases proportionally with the square of distance (the same as real world light) |
3 | light intensity decreases proportionally with the cube of distance (faster than real world light) |