cloud distribution and size

isugath · August 23, 2009, 11:01:31 AM

hello!

sorry if there is a similar topic, i could not find

i've got a few problems with my cumulus clouds.
the main problem is the distribution and size of the clouds.
i was going for a look like this -> http://community.webshots.com/photo/fullsize/1084389937048554426hiNqma
and what i've come up with so far is this -> http://img44.imageshack.us/img44/8459/clouds09.jpg
i think the look of the clouds themselves is allright so far (allthough i would like the cumulus-effekt to be stronger.. maybe you got some ideas therefore too? )
but as you can see in my reference photo, the clouds tend to "gather" in an area and build greater cloud formations in one area, whereas other areas are cloudless.
i tried the leadin and feature scale, with which i get near the distribution i would like, but they change the overall look of my clouds as well.
i also tried to connect an other map, for example another fractal into the blend shader of the cloud distribution shader, which would get rid of some clouds and give me these cloudless areas, but this "mask" changes the borders of my clouds which is also not ideal.

so..
1. is there any way i could get this "great cloud gathering while some areas are cloudless" -effect without changing the overall look of the clouds themselves?
2. how can i make the cumulus effekt stronger to get my clouds look a bit more like these (for example) -> http://upload.wikimedia.org/wikipedia/commons/a/a2/Cumulus_toronto_June_2008-18.JPG

thanks!
dave

Tangled-Universe · August 23, 2009, 11:12:08 AM

To make clouds "gather" in certain areas you'll have to use a mask/blendshader.

Create a new powerfractal and set the contrast and roughness to about 2. Set the offset to -0.5 or smaller.
Use this powerfractal as blendshader for your cloudfractal.
Your clouds will look the same, but will only "gather" in the whitest parts of your blendshader (the powerfractal).

To get billowy clouds I recommend to start with contrast of ~1 and noise of ~1.5.
The cloud-node (light-blue one) needs either a great value for edge sharpness (~50 for example) and low density (~0.1) or vice versa (low sharpness, huge density).

This should get you going for now I hope

Martin

aymenk2003 · August 23, 2009, 12:38:13 PM

thanks Martin... this gives a lot of help

isugath · August 23, 2009, 02:59:04 PM

thanks martin
but it seems im still doin something wrong.. i just can't get the look i'd like.
i tried your values which didn't get me the result i wanted. after starting over a few times now, i'm starting to think that i'm either simply unable to handle the clouds the right way, or its just not possible the way i'm trying it.

so.... another question.. has anyone created real looking culumus clouds like these -> http://image07.webshots.com/7/8/99/37/84389937hiNqma_fs.jpg using only the standard cumulus layer and the density fractal, or do i have to get to an advanced level of funktions and operations to get such an result?

thanks,
dave

aymenk2003 · August 23, 2009, 03:58:18 PM

I did follow Martin advice and after a little tweak I end up with something ...!!!
Is that what you are looking for ??
*EDit: the Camera is at 3500 m...

isugath · August 23, 2009, 05:41:20 PM

well.. technically its the right direction.
i had similar results to yours, but it seems this effect is pretty depending on the size of the clouds, which is much to big in your example.
i think its pretty hard to describe where i want to get with this.
i know it seems you would just have to decrease the coverage a bit and roughness and here and there a bit tweaking,.. but after a few tweaks i realize that its lookin completely different and not really closer to my reference..

maybe i just lack of expirience and patience at this point...

so please.. im thankfull for any tips you might got

aymenk2003 · August 23, 2009, 05:55:12 PM

may you have to visit this file sharing link witch deals with cloud only...
http://forums.planetside.co.uk/index.php?topic=3691.0

NKAID...

isugath · August 23, 2009, 06:28:16 PM

thanks aymenk2003, i'll definitely have a look at this one!

FrankB · August 23, 2009, 06:29:07 PM

You mean something like this, don't you?

http://forums.planetside.co.uk/index.php?topic=6885.msg73228#msg73228

Frank

isugath · August 23, 2009, 06:37:09 PM

EXACTLY!
..except with more cloudless areas, but let's not be fussy now

Tangled-Universe · August 23, 2009, 06:51:18 PM

Quote from: isugath on August 23, 2009, 06:37:09 PM
EXACTLY!
..except with more cloudless areas, but let's not be fussy now

you know how to get cloudless areas now, I explained you that in my previous post

For getting started on cumulusses...I just remembered this post:
http://forums.planetside.co.uk/index.php?topic=5490.msg56723#msg56723

isugath · August 24, 2009, 04:24:40 PM

Quote from: Tangled-Universe on August 23, 2009, 06:51:18 PM
you know how to get cloudless areas now, I explained you that in my previous post

well.. right..
i still got a problem with that...
i tried the method you suggested, but the problem with this is the following.
for better understanding of my point, lets say i "mask" the clouds by a imagemap i painted in photoshop. a simple, soft gradient in the middle, so that the clouds "gather" there. but now the clouds in tg react like this. imagine i rendered two images. one with my normally distributed clouds, whithout the wanted gathering-effect. and one without clouds, only tarrain. and now (when used the above described technic, it looks like as if i took these two layers in photoshop, and painted a soft mask für the layer with the clouds.
like this -> http://img34.imageshack.us/img34/6532/clouds11.jpg

now i know, that you suggested to use a fractal with specific values, but i would have to tweak these values again to get the edge look i want. i think that would be a rather impractical way.

it would be much better, if this mask i paint (or do by fractal), would effect the cloud distribution in another way, like.. "where this mask is white, the clouds are "emitted" as they are without mask, and where the mask is black, they are not "emitted".

like this example (created in photoshop)

the mask ->
http://img30.imageshack.us/i/themask.jpg/

the result ->
http://img32.imageshack.us/i/theresult.jpg/

is it somehow possible to do that, or do i have to adjust the values of my second fractal that blends into my cloud distribution so that the edges of my clouds are what i would like them to be again?

about the cumulus clouds: thank you very much for your link, Tangled-Universe! these clouds are really amazing and i'm sure i can learn pretty much from them

thanks for your patience and help!

Tangled-Universe · August 24, 2009, 05:17:18 PM

What you describe is not the way TG2 uses your image as a mask.
It is not the same as with photoshop that TG2 blends the clouds with the terrain.
The mask masks the density fractal of the cloud. This masked fractal then creates the clouds in the masked areas. This happens in 3D space and not in 2D like in photoshop.

You probably did something wrong, so therefore I made some examples for you to show how you can mask clouds. The .tgd-file offers examples of fractal, image and distance shader based masking of the cloudfractal.

Hope this will help in your understanding how masking in TG2 works.

Cheers,
Martin

isugath · August 24, 2009, 05:55:09 PM

Quote from: Tangled-Universe on August 24, 2009, 05:17:18 PM
What you describe is not the way TG2 uses your image as a mask.
It is not the same as with photoshop that TG2 blends the clouds with the terrain.
The mask masks the density fractal of the cloud. This masked fractal then creates the clouds in the masked areas. This happens in 3D space and not in 2D like in photoshop.

erm.. i'm sorry.. i must have described it pretty bad

i know, of course, that the masking happens in 3d. what i meant was, that it looks like it was blended in photoshop.

if its not possible the way i would like it too, i will have to work with that whats available.

i will have a look at your examples first thing tomorrow morgning.. thank you again for your help!
hopefully i will be able to create some neat looking clouds soon, to show you that it was not gratuitous

edit: allright! all clear about masking off clouds for me now

thanks!
allthough it would be nice if it would work the way i meant above.
because the way its possible now, you have to configure the borders of the clouds 2 times. first for the clouds themselves, and a second time for the border of the "gathering".
you get my point, or is it senceless, what i'm talking about?

dave

Hetzen · August 25, 2009, 03:58:33 AM

I understand exactly where the OP is coming from. The cloud shader would be so much more powerful if we could modulate altitude/depth and scales with other PFs. You could then more or less create a global weather pattern with say just 3 cloud nodes with tremendous variation. At the moment, the problem with TG is the 'flatness' you get when looking down towards the horizon.

I have a job coming up with Lockhead Martin, and this feature would guarantee me using TG in that pipeline, the cost saving on air to air shots would make us very competitive.