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General => Terragen Discussion => Topic started by: MGebhart on February 28, 2010, 07:24:26 PM

Title: Clouds are a *****
Post by: MGebhart on February 28, 2010, 07:24:26 PM
I was working with clouds today. Not just a basic cloud layer, adjusting samples and so on. I wanted to create the big bad cumulus kind. It's not easy.

Here is what I came up with after a half a day effort.

HELP! What a mess.

Marc
Title: Re: Clouds are a *****
Post by: TheBlackHole on February 28, 2010, 08:45:46 PM
Ugh, I know. I had trouble making the clouds for my asteroid impact (it's in File Sharing)(sorry, no pic. Render one yourself! ;D) I just cloudn't (pun intended) get the explosive look the original had (lost it when someone rebooted my computer via the "reset" button :( ).
Title: Re: Clouds are a *****
Post by: Henry Blewer on February 28, 2010, 09:20:26 PM
Marc, the clouds density is set too high. The default of 0.01 is usually good. I sometimes halve this value. I would also lessen the edge value. High values can make the clouds look solid.
Title: Re: Clouds are a *****
Post by: choronr on March 01, 2010, 01:10:54 AM
Agree with Henry's assessment. And, you might experiment with 'flat bottom' clouds in this instance. Looking forward to your progreee.
Title: Re: Clouds are a *****
Post by: old_blaggard on March 01, 2010, 01:30:34 AM
In your noise function, a good rule of thumb for cumulus is to have the feature scale be about 1/4 the size of the lead-in scale. Try starting out with 5000 and 20,000 respectively.
Title: Re: Clouds are a *****
Post by: reck on March 01, 2010, 08:06:33 AM
I would say clouds are probably the most difficult aspect of Terragen to learn.

You could purchase the cloud pack from NWDA to see how the experts do it, but then you still need to understand what all the nodes are doing.
Title: Re: Clouds are a *****
Post by: Henry Blewer on March 01, 2010, 08:11:18 AM
I have been playing with voronoi noise lately. Simple stuff. Try adding a 'A' type to the density shader. Plug a Get geometry  into the voronoi's input and set the scale and seed by hand. Mixing several types from large to small may be a good way to get the puffy look.
Title: Re: Clouds are a *****
Post by: MGebhart on March 01, 2010, 09:38:19 AM
Thanks for the tips.

Here is another render. Getting closer but no cigar.

Henry, I can't figure out the Voronoi 3D A Vector noise and the Get geometry. I get multi colors throughout the render. So, I'm sure my wires are not input correctly.

Marc
Title: Re: Clouds are a *****
Post by: j meyer on March 01, 2010, 10:30:05 AM
Hi,
there are several example files that have been posted earlier on these
forums and amongst them there should be one by the celebrated Luc Bianco,
iirc he posted it in one of FrankB's threads.Try the search engine,please.
Title: Re: Clouds are a *****
Post by: Henry Blewer on March 01, 2010, 12:19:59 PM
Put the merge shader into the density shader's input. It should negate the colors and do the displacements.
Title: Re: Clouds are a *****
Post by: MGebhart on March 01, 2010, 03:49:31 PM
You guys rock.

Thank you.

I'll post another result when I get it rendered.

Marc
Title: Re: Clouds are a *****
Post by: MGebhart on March 01, 2010, 08:37:26 PM
OK. This is my next iteration. I think I'm getting closer however, I need more contrast in the cloud color and the bottom looks kinda strange to me.

This is a fairly low res render. I noticed as you build these babies the rendering time increases exponentially.

Marc
Title: Re: Clouds are a *****
Post by: Henry Blewer on March 01, 2010, 08:46:38 PM
Try a lower cloud density. This is starting to shape up. edit : (Not the coverage value)
Title: Re: Clouds are a *****
Post by: TheBlackHole on March 02, 2010, 05:17:54 PM
And I think you should use a brighter cloud color.
Title: Re: Clouds are a *****
Post by: CCC on March 02, 2010, 05:56:30 PM
Yes, the clouds are missing that silver lining highlight along there tops. Overall they should be brighter as well without washing out the distinctive details.
Title: Re: Clouds are a *****
Post by: MGebhart on March 05, 2010, 10:39:57 PM
Here's another shot.

Marc
Title: Re: Clouds are a *****
Post by: choronr on March 05, 2010, 10:50:42 PM
Now you've got it Marc. All that is needed is a small crackle of lightening under the cloud in the distance. Very good.
Title: Re: Clouds are a *****
Post by: Henry Blewer on March 05, 2010, 11:27:54 PM
Whao! That's a big, beautiful cloud!
Title: Re: Clouds are a *****
Post by: TheBlackHole on March 06, 2010, 12:24:15 AM
Agree with choronr. Add a light purple light source under the cloud, right at the base. RGB 145, 72, 255 would be nice.
Title: Re: Clouds are a *****
Post by: tempaccount on March 07, 2010, 05:24:52 AM
I'm curious as how to get that fine detail in the clouds - for some reason my clouds always end up looking.. flat and not bumpy at all, no matter where I position the sun.

Is it something to do with the noise settings or more with the lighting and density settings?
Title: Re: Clouds are a *****
Post by: Tangled-Universe on March 07, 2010, 07:52:39 AM
Quote from: tempaccount on March 07, 2010, 05:24:52 AM
Is it something to do with the noise settings or more with the lighting and density settings?

Unfortunately with all of these aspects, that's why it's so difficult :(

I made an attempt on this using the work of Frank on cumulus clouds, see here please:
http://forums.planetside.co.uk/index.php?topic=9115.0 (http://forums.planetside.co.uk/index.php?topic=9115.0)

If you do auto-levels on this picture you'll see it has awesome details, but it is very very hard to get it just right.
Title: Re: Clouds are a *****
Post by: Tangled-Universe on March 12, 2010, 06:12:37 AM
Another one here:

http://forums.planetside.co.uk/index.php?topic=9162.0 (http://forums.planetside.co.uk/index.php?topic=9162.0)
Title: Re: Clouds are a *****
Post by: tempaccount on March 12, 2010, 08:38:44 AM
Well, I suppose moving the atmosphere settings (and clouds) as the first thing to do in my new workflow was a good call :p