Clouds Question

Started by tomglod, March 25, 2009, 05:15:04 PM

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tomglod

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Hi guys,

how do you make clouds like this?

I try low level and mid level 3d clouds...and crank up the desnity but they all still come out pretty flat.

any help would be appriciated.

Thanks,

Tom

PS> I did a search on the forum and couldn't find an answer.... I'm sorry if its been asked before.

FrankB

That's actually fairly easy to achieve. Here are the 2 things you should do:
1 - lower the gamma in the tweaks tab of the cloud layer to below 0.3 (to begin with)
2 - increase the density in the cloud fractal until your sky is covered again

what this does in simple terms is that the reduced gamma brings out the vertical features of the clouds more. This is really very much simplified but you can look at it this way. The side effect is that less features from the cloud fractal qualify for being rendered, and only a fraction of the fractal features are above pure white (below a certain level of grey the cloud won't show / render, and above a certain level of white the have the max height, which can look like a flat white area when seen from above). So to make up for it, you have to increase the coverage a lot.

Frank

Mohawk20

You got it from the master...
If you do what he said, it will definitely work.
Howgh!

cyphyr

Excellent explanation, thanks Frank. I now understand a little more what the gamma's there for :)
richard
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tomglod

thanks you brother...i haven't tried it yet...but if you are the master then I have perfect faith.

FrankB

I should have been more precise I think.
I forgot to mention that you need to take care that the feature size in the fractal does not exceed the cloud depth. In fact, it's helpful if the cloud depth is larger thatn the feature size. Otherwise, you will continue to see the flat areas. If you want to mimic the photo with tg2, you need a relatively small feature size and a relatively large lead-in scale. Try to begin with 400 for feature scale and 30000 for lead-in. The feature scale will determine what the dominant sizes inside a cloud will be. The 400 are your little billowry cushions. The 30000 is the size of the area on which the little billows will clump together. In other words, you'll have an up to 30km wide field of little billows.

I've attached a no-frills tdg for you to begin with.

Frank





rcallicotte

Gosh, Frank.  Thanks for this explanation and a file.  Whoa.
So this is Disney World.  Can we live here?

FrankB

you are most welcome!

Frank

Mr_Lamppost

I know you have posted both the explanation and example here, which is great and appreciated but would it be worth adding them to the Cloud Library in the file sharing section so that people can find them later on?

I have just spent half an hour tracking down a post I had made last summer so I could point someone to an answer to their question. ;D
Smoke me a kipper I'll be back for breakfast.