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Hi!
I've experimented a little bit with procedural clouds (written with
shader) and here is most promising result. Basically it is one plane
with shader. Shader is quite messy right now, but basically it performs
marching from intersection point toward light source and uses "advanced
calculation" to calculate cloud's color. So the shadowing of clouds is
totally fake, but with little more tinkering it could be possible to
make this fake quite believable. But right now every attempt leads to
worse output, so I have to take time off.
Good part of such approach is that it renders quite fast: 512x384 aa0.3
on 2m28sec (350 MHz P2)
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Preview of image 'cloudover.jpg'
![cloudover.jpg](/povray.binaries.images/attachment/%3C3AAFBF12.BF398D9D%40aetec.ee%3E/cloudover.jpg?preview=1)
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Vahur Krouverk <vah### [at] aetec ee> wrote in message
news:3AAFBF12.BF398D9D@aetec.ee...
> Hi!
>
> I've experimented a little bit with procedural clouds (written with
> shader) and here is most promising result. Basically it is one plane
> with shader. Shader is quite messy right now, but basically it performs
> marching from intersection point toward light source and uses "advanced
> calculation" to calculate cloud's color. So the shadowing of clouds is
> totally fake, but with little more tinkering it could be possible to
> make this fake quite believable. But right now every attempt leads to
> worse output, so I have to take time off.
> Good part of such approach is that it renders quite fast: 512x384 aa0.3
> on 2m28sec (350 MHz P2)
Not bad!
I recently implemented a real-time clouds simulation at work (I work in the
games industry), so confidentiality probably prevents me from saying too
much :-(. But I recommend you have a look here:
http://www.eml.hiroshima-u.ac.jp/~doba/pub_doba.html
What I did was based entirely on the second paper there, called "A Simple,
Efficient Method for Realistic Animation of Clouds". It's just about
possible in real time (though we'll probably drop it because it's a bit
expensive) but if you're pre-rendering you could get ridiculously realistic
clouds :)
I hope this is of some help.
--
Tek
"There's definitely, definitely, definitely no logic... to human
behaviour." - Bjork
http://www.evilsuperbrain.com
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Hey, cool. Keep up the good work. You're getting there. :) C'mon, we all
want fast clouds... :)
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Tekno Frannansa wrote:
>
>
> Not bad!
>
> I recently implemented a real-time clouds simulation at work (I work in the
> games industry), so confidentiality probably prevents me from saying too
> much :-(. But I recommend you have a look here:
> http://www.eml.hiroshima-u.ac.jp/~doba/pub_doba.html
>
> What I did was based entirely on the second paper there, called "A Simple,
> Efficient Method for Realistic Animation of Clouds". It's just about
> possible in real time (though we'll probably drop it because it's a bit
> expensive) but if you're pre-rendering you could get ridiculously realistic
> clouds :)
>
> I hope this is of some help.
>
Thanks for input. I believe that I looked at this paper, when I browsed
siggraph materials at ACM site. I've seen other papers there as well,
which use various approaches for cloud rendering. Perhaps if I have more
time, then I'll try them. But this attempt is based on Katsu's (Katsuaki
Hiramitsu's) approach. At least I believe that it is similar technique,
for he doesn't want to publish shader for this stunning picture (
http://www.edit.ne.jp/~katsu/image/cloud.jpg ), but he was kind enough
to give some hints about used method. So, time providing, I try to hack
it further to get more pleasing results.
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Hi!
Here is take 2. Unfortunately I don't have time right now to develop (or
more correctly: hack) it further (I will be off 2 weeks on the mountains
for heliboarding trip :-), so I made source code available in my
homepage ( http://www.aetec.ee/fv/vkhomep.nsf/pages/shdrex/ ).
If someone obtains better results with this approach, then it would be
good to see them.
Previous version suffered severly from noise plateau effect, as I forget
to set version to unofficial. This picture is more pleasing hopefully...
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Preview of image 'cloud2.jpg'
![cloud2.jpg](/povray.binaries.images/attachment/%3C3AB105FF.DB8E4950%40aetec.ee%3E/cloud2.jpg?preview=1)
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in <3AB105FF.DB8E4950@aetec.ee> Vahur Krouverk wrote:
>--------------267C7910C11B2C7BA34DD473
>Hi!
>
>Here is take 2.
The structure of clouds is definatly there, but it lacks depth.
>Unfortunately I don't have time right now to develop
>(or more correctly: hack) it further (I will be off 2 weeks on the
>mountains for heliboarding trip :-),
"Hals und Beinbruch"
> ...
Ingo
--
Photography: http://members.home.nl/ingoogni/
Pov-Ray : http://members.home.nl/seed7/
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Vahur Krouverk wrote:
>
> Hi!
>
> Here is take 2. Unfortunately I don't have time right now to develop (or
> more correctly: hack) it further (I will be off 2 weeks on the mountains
> for heliboarding trip :-),
Why, you "/$%?*(()?%$())%@#!!!
--
Francois Labreque | And a four year old carelessly banging on a toy
flabreque | piano is not only 'music', it's probably the last
@ | moment of 'artistic purity' they'll ever enjoy
videotron.ca | before outside influences start corrupting their
| expression. - Chris R.
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ingo wrote:
>
> The structure of clouds is definatly there, but it lacks depth.
>
Right, perhaps this is better? (source is in my homepage)
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Preview of image 'cloud4.jpg'
![cloud4.jpg](/povray.binaries.images/attachment/%3C3AB1DF66.E23ECDDB%40aetec.ee%3E/cloud4.jpg?preview=1)
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> Why, you "/$%?*(()?%$())%@#!!!
That's French for "Have a great time, you lucky fellow!". ;)
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Vahur Krouverk wrote:
> ingo wrote:
> >
> > The structure of clouds is definatly there, but it lacks depth.
> >
> Right, perhaps this is better? (source is in my homepage)
The shading effect is great, but what I think contributes some to the harsh
two-dimensionality is the edges. I haven't had a look at the source yet, but
is there a way you can make them blend into the sky a bit?
--
David Fontaine <dav### [at] faricy net> ICQ 55354965
My raytracing gallery: http://davidf.faricy.net/
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