It is the key to lighting an indoor scene.

Very briefly:

Luminance is like temperature - it has to do with the amount of light energy within a given area. As the light energy moves away from the source, it is always spreading out over a larger and larger area. Since the amount of energy is not changing, but the area is increasing, that light gets spread thinner and thinner, appearing weaker.

The math is simple. The luminance is inversely proportional to the square of the distance from the light. Do not say your head exploded. This is nonsense I hear all too often. If you are in a society where it is shameful to be able to understand a simple math formula with only 3 terms in it, then go hide under a blanket and READ THIS.

Let's say "d" is the distance between some prop and the light source.

d is distance

Let's say "I" is the intensity (strength) you choose for the light in Poser.

I is Intensity

Ready? The illumination from any light should be

I / (d^2)

That's I divided by d squared. Inverse square falloff.

It is neither difficult to understand, nor expensive to compute. It is an enormously obvious physical effect, and without it indoor lighting looks totally fake.

Yet, Poser lights do not implement this formula. We need not explain why such a fundamental fact of the universe was ignored in Poser, despite it being trivial to calculate. We need only find a way to add it to the calculation.

Thus was born my Inverse Square Falloff (ISF) light shader.

I don't know where it is at the moment, but I'm sure somebody can point you to the thread.

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)