Clouds settings: Light Propagation and/or Light Propagation Mix???

Started by Tangled-Universe, February 29, 2008, 07:51:30 AM

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Hello everybody,

Last time I've been concentrating myself on trying to achieve some realistic cloud formations and I'm slowly progressing.
One thing that still "holds me up" is a true understanding of some of the clouds' settings.

I was wondering if anyone could give a decent explanation of the cloud settings "Light Propagation" and "Light Propagation Mix".
Fake internal scattering is quite clear to me, but I can't figure out how Light Propagation and Light Propagation Mix work and/or work together.

I'm aware of a site where many cloudsettings are compared (can't come up with the name right now) but it wasn't of real help to me.



Nope.  Outside of the common understanding of the words, I've never paid attention to these settings.  Nevertheless, I'd like to understand these as well.
So this is Disney World.  Can we live here?


From what I know....

Light propagation usually works well when you have sun within the field of view of the camera and there are clouds covering the sun....

lower the number, more light is "trapped and scattered" in the clouds making them look dense

higher the number, more light gets through the clouds (watch the shadows on the ground)

and I havent played much with light propagation mix but I think this option controls the variation in scattering (not sure).....

some examples

first image has LP of zero
sencond one has LP of 20

I have also included the tgd

the difference is easy to understand
"His blood-terragen level is 99.99%...he is definitely drunk on Terragen!"

Volker Harun

I believe (!) that the LP mix controls the strength of Fake internal scattering vs LP. A value of 0 only goes for Internal Scattering and a value of 1 does LP only.

I am not sure and I like to be proofed wrong :-)


I have made some experiments with some of the advanced cloud settings but wouldn't say I have been overly successful at gaining a proper understanding of the way they work.  Scattering Colour definitely doesn't work the way I expected but that may be down to the Propagation Mix setting I used; assuming Volker is right.  :)

Any idea how to use Fake Dark?
Smoke me a kipper I'll be back for breakfast.