Mike,
if the decrease is linear, and at 256 units the light has lost 25% of its
power, then should I assume that at >= 1024 units, a white plane facing the
light would have zero brightness, right? Nope. Here are some results from a few
test renders I did while composing this message:
Distance Object brightness
——– —————–
2048 31
1024 63
512 123 (127, basically)
256 249 (255, basically)
Distance was approximate (set grid to 256, moved plane interactively rather
than using Transform requester). As you can see, illumination doesn't decrease
until the object is 256 units away from the light; from then on, the decrease
is not linear, but inverse-exponential.
Blaq!