In article <3fadfd40@news.povray.org>, "gonzo" <rgo### [at] lansetcom> wrote:

> Ah, so reflection (and probably specular or phong) will still see it
> correctly as long it's <1. That's probably what I'm seeing.

Reflection and other features will see it correctly no matter what the 
brightness is. Anything brighter than 1 will be clipped to 1 when the 
image is written to a file. If you make a very dark filter and put it in 
front of the camera, you will see the shading that you couldn't before.


> > So with a fade_distance of 1 and fade_power 2, the light intensity from
> > your < 7.5, 5, 1> light source at a distance of 5 units will be:
> > < 0.576923077, 0.384615385, 0.0769230769>
> 
> It's distances less than fade_distance I'm most interested in.

Those get brighter, up to 2x brighter than the specified light source 
brightness.


> The main reason I use high fade_power is to simulate sunlight which is
> waaaay bright, but seldom pure white.

This is highly inaccurate. At the distance of Earth's orbit, sunlight is 
essentially constant over any planetary distances. The sun is 
practically as bright on the moon as in near earth orbit, no matter what 
their relative positions are. You certainly aren't going to see any 
difference at smaller scales.
Light fading is only useful for situations where you are close to the 
source of the light or can see objects that have widely varying 
distances from the light.


> So I set the color I want the light to
> be then boost fade_power way up.

And this is the wrong way to adjust brightness...you should adjust 
fade_distance instead. BTW, I've done some more testing, and fade_power 
3 actually approximates inverse-square falloff more closely, at least as 
long as distance > fade_distance.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

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