Inverse Linear Inverse Square Created 12 years ago2012-08-24 15:41:24 UTC by Bruce

Anybody could explain what these ZHLT flags do in light settings?

I don't know specifically in mapping, but in lighting terms they refer to falloff.

Inverse linear is exactly what it says on the tin - a linear gradient where the light will fall from full intensity to 0 over a distance or percentage specified.
Inverse Square refers to how light actually behaves in reality, and can be calculated thusly:

Illumination = Luminosity divided by Distance squared.

In plain English: An object twice the distance from the light source will receive only a quarter of the illumination of the source.

Have you did any comparison tests?

Only in After Effects.

So I guess we should use Inverse Square everywhere. Is there a RAD command to apply this to all lights, including texture lights?

No idea, like I said, I've never used it in mapping except to manually calculate falloff in Source's spotlights.
Sorry, dude!

I see.. I'm a bit confused

I = K/D^2 with K being a constant. As archie pretty much completely explained, as the distance increases, the light intensity ( or let's just say for mapping's sake the brightness) decreases exponentially.

I wonder why is there an option left for it at all if it's more correct in all cases. Instant, do you use it?

Archie, what you meant by "manually calculate falloff in Source's spotlights"?

Source spotlights have the following properties that can be used to fine-tune falloff to an utterly anal degree:

Constant
Linear
Quadratic
50% Distance
0% Distance
Hard Falloff
Focus

And you do it to make a spotlight longer/shorter or what? Wouldn't changing brightness do the same?