Search

 

Clouds following terrain

Started by mhaze, November 23, 2008, 07:56:55 AM

Previous topic - Next topic
Print
Go Down Pages1 2
User actions

mhaze

November 23, 2008, 07:56:55 AM
Hi All

After a walk in the welsh hills last week, when I was treated to an amazing display of cloud effects, I was inspired to attempt to create the effect of clouds following the terrain.

I enclose a screenshot of progress so far based on the work of Mr Lampost. L have been trying to subtract the heightfield ffrom the clouds apart from the fact that it is hard to see if I'm having any effect, I'm stuck and I have the feeling that it will be impossible to achieve this as there seems to be no way to control the height of the clouds procedurally.

If there is no way of doing this, Matt please can we have the facility in the next upgrade, please, please, please.

Mick

JimB

#1
November 23, 2008, 08:02:45 AM
I think one approach is perhaps to have multiple layers of clouds all using the same Density Fractal and intersecting each other, and then mask each layer according to the underlying terrain height to give the illusion of the clouds following the terrain below. Asked the question myself before and there wasn't a way then, but who knows now?

http://forums.planetside.co.uk/index.php?topic=370.msg2604#msg2604
Some bits and bobs
The Galileo Fallacy, 'Argumentum ad Galileus':
"They laughed at Galileo. They're laughing at me. Therefore I am the next Galileo."
Nope. Galileo was right for the simpler reason that he was right.

Mohawk20

#2
November 23, 2008, 12:01:18 PM
I have an idea...

Make the cloud layer as thick as the terrain (so lowest and highest point same as the terrain). And then paint the terrain with the painted shader. Set the painted shader to 3d, and use it as blend shader for the cloud's density fractal.
The painted shader should make the clouds float between the terrain and a few units above it, depending on the colour's intensity.

I have not tried it in this situation, but it worked for my waterfalls in the Hanging Valley project...
Howgh!

neon22

#3
November 23, 2008, 01:12:20 PM
Has anyone tried inverting a distribution shader
- attached to the terrain
- (setting the min max height to the desired cloud range)
and using that as the Blendshader ?

mhaze

#4
November 23, 2008, 05:21:03 PM
thanks for tsuggestions

but so far I can't make things work as expected :(

Mick

FrankB

#5
November 23, 2008, 05:31:05 PM
 does "cloud following terrain" mean anyway? I have no idea...

neon22

#6
November 23, 2008, 05:58:07 PM
The way clouds will not intersect with the terrain but instead be off the surface.
E.g. winds and temperature differences can act as an interface layer between the clouds and the terrain.

neon22

#8
November 23, 2008, 11:35:00 PM Last Edit: November 23, 2008, 11:37:29 PM by neon22
I thought maybe something like this would work. but it doesn't.
hey Big ben - when it comes to masks like this - you're the man.
Any ideas ??

The distribution mask is looking good but the Transfrom shader does not seem to be working...

FrankB

#9
November 24, 2008, 02:54:48 AM
ah, thanks to the photo examples I now know what this is about. Thanks,
Frank

bigben

#10
November 24, 2008, 04:28:42 AM
Quote from: neon22 on November 23, 2008, 11:35:00 PM
I thought maybe something like this would work. but it doesn't.
hey Big ben - when it comes to masks like this - you're the man.
Any ideas ??

The distribution mask is looking good but the Transfrom shader does not seem to be working...

I was thinking along a similar line.  generating a parallel terrain for the mask.  Terrain > Displacement shader (add height to reach cloud altitude, Function = scalar constant of 1) > Text coords from XYZ > Surface shader (white) > Cloud density blending shader

Still rendering the rest of my cloud animation so I haven't tried this out yet.  I could be completely wrong here though....  ;) 

mhaze

#11
November 24, 2008, 08:22:14 AM
This sorta works....

mhaze

#12
November 24, 2008, 08:58:50 AM
QuoteI was thinking along a similar line.  generating a parallel terrain for the mask.  Terrain > Displacement shader (add height to reach cloud altitude, Function = scalar constant of 1) > Text coords from XYZ > Surface shader (white) > Cloud density blending shader

Sorry big ben just tried it and does not work, could be me though.

freelancah

#13
November 24, 2008, 09:28:19 AM
This is a dilemma that I've been trying to figure out with very little success. Glad to see you guys are working on it too. I will post my work if I am able to get it working

mhaze

#14
November 24, 2008, 10:15:56 AM
Quite unexpected - using an image map - all settings at default

Off to play

Mick
Print
Go Up Pages1 2
User actions