Rune wrote:
> 
> Yet another of those stacked plane cloud methods!
> 
> On my website I've uploaded the code for the sky I'm using for my WIP desert
> landscape image as seen in povray.binaries.images. I've gotten a request for
> the code, and also saw a general request for stacked plane clouds here
> recently.
> 
> My approach is not the most realistic maybe, but as it uses four planes
> only, it renders very fast.
> 
> If you're interested, have a look at
> http://rsj.mobilixnet.dk/3d/goodies/goodies.html
> 
> Please let me know what you think. :)
> 

Looks fairly good for only 4 layers.  And it looks quite a bit different
from the usual 1 layer texture clouds.  

For me personally it usually does not matter that much whether the clouds
take 1 or 10 minutes to render...

Christoph

-- 
POV-Ray tutorials, IsoWood include,                 
TransSkin and more: http://www.tu-bs.de/~y0013390/  
Last updated 18 Mar. 2002 _____./\/^>_*_<^\/\.______

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"Christoph Hormann" wrote:
> Looks fairly good for only 4 layers.

Thanks!

> And it looks quite a bit different
> from the usual 1 layer texture clouds.

I sure hope so.

> For me personally it usually does not matter that much
> whether the clouds take 1 or 10 minutes to render...

That matters very much for me, especially in this case where I need it for
an animation.

Rune
--
3D images and anims, include files, tutorials and more:
Rune's World:  http://rsj.mobilixnet.dk (updated Feb 16)
POV-Ray Users: http://rsj.mobilixnet.dk/povrayusers/
POV-Ray Ring:  http://webring.povray.co.uk

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"Tim Nikias" wrote:
> You're missing the
> global_settings{assumed_gamma 1}!

Why? It looks awful when I use that setting.

Rune
--
3D images and anims, include files, tutorials and more:
Rune's World:  http://rsj.mobilixnet.dk (updated Feb 16)
POV-Ray Users: http://rsj.mobilixnet.dk/povrayusers/
POV-Ray Ring:  http://webring.povray.co.uk

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Of course it does.
First set assumed_gamma 1 THEN code textures (and lights). You'll have to mentally
re-build all your assumptions on colors and finishes, but it's definitely worth it.

BTW very nice sky, esp. since you used only 4 planes.

--
Jonathan.

"Rune" <run### [at] mobilixnetdk> ha scritto nel messaggio
news:3c97afe9@news.povray.org...
> "Tim Nikias" wrote:
> > You're missing the
> > global_settings{assumed_gamma 1}!
>
> Why? It looks awful when I use that setting.
>
> Rune
> --
> 3D images and anims, include files, tutorials and more:
> Rune's World:  http://rsj.mobilixnet.dk (updated Feb 16)
> POV-Ray Users: http://rsj.mobilixnet.dk/povrayusers/
> POV-Ray Ring:  http://webring.povray.co.uk
>
>

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"JRG" wrote:
> Of course it does.
> First set assumed_gamma 1 THEN code textures (and lights).
> You'll have to mentally re-build all your assumptions on
> colors and finishes, but it's definitely worth it.

Nah, there must be more to it than that, maybe display_gamma must be set or
something.

When simply using assumed_gamma 1, the results I get are wrong. A white
pigment in shadow, which should be 10% white looks more like 60% white,
which is way too bright. When I don't specify any assumed_gamma it looks
like 10% white as it should. My monitor gamma is about 2.2, which is the
default.

> BTW very nice sky, esp. since you used only 4 planes.

Thanks!

Rune
--
3D images and anims, include files, tutorials and more:
Rune's World:  http://rsj.mobilixnet.dk (updated Feb 16)
POV-Ray Users: http://rsj.mobilixnet.dk/povrayusers/
POV-Ray Ring:  http://webring.povray.co.uk

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Rune wrote:
> 
> [...]
> When simply using assumed_gamma 1, the results I get are wrong. A white
> pigment in shadow, which should be 10% white looks more like 60% white,
> which is way too bright. 

There is no complete shadow in your scene and with a light source of color
rgb 3 you should expect it being bright.

Christoph

-- 
POV-Ray tutorials, IsoWood include,                 
TransSkin and more: http://www.tu-bs.de/~y0013390/  
Last updated 18 Mar. 2002 _____./\/^>_*_<^\/\.______

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"Christoph Hormann" wrote:
> There is no complete shadow in your scene and with a
> light source of color rgb 3 you should expect it being bright.

You seem to assume I'm talking about that cloud scene? I'm not. This is my
test scene:

// global_settings{assumed_gamma 1}
light_source {<1,2,-2>*100, rgb 1}
sphere {3*z, 1 pigment {rgb 1}}

Rune
--
3D images and anims, include files, tutorials and more:
Rune's World:  http://rsj.mobilixnet.dk (updated Feb 16)
POV-Ray Users: http://rsj.mobilixnet.dk/povrayusers/
POV-Ray Ring:  http://webring.povray.co.uk

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"Rune" <run### [at] mobilixnetdk> ha scritto nel messaggio
news:3c97b9c3@news.povray.org...
> "Christoph Hormann" wrote:
> > There is no complete shadow in your scene and with a
> > light source of color rgb 3 you should expect it being bright.
>
> You seem to assume I'm talking about that cloud scene? I'm not. This is my
> test scene:
>
> // global_settings{assumed_gamma 1}
> light_source {<1,2,-2>*100, rgb 1}
> sphere {3*z, 1 pigment {rgb 1}}

The default finishes (esp. ambient is way too high) do not match well with
assumed_gamma 1.
This worked for me:

global_settings {
    ambient_light 0
    assumed_gamma 1
}

#declare White_Texture =
texture {
    pigment {
        rgb 1}
    finish {
        ambient 0
        diffuse 0.75
        specular 0.65
        roughness 0.008
        reflection {0.03,1 falloff 5}
    }
    normal {
        bumps 0.05 scale 1}
}

sphere {
    3*y+5*z,3
    texture {
        White_Texture scale 0.08}
}

plane {y,0
    pigment {rgb 0}
    finish {ambient 0
        diffuse 0.8  specular 0.5 roughness 0.01 reflection 0.2
    }
}

light_source {
    <0,140,0>
    rgb 1
    area_light 30*x,30*z,5,5 adaptive 0 jitter circular orient
    fade_power 2
    fade_distance 100
}

light_source {
    <-30,80,-99>
    rgb 1
    area_light 10*x,10*y,5,5 adaptive 0 jitter circular orient
    fade_power 2
    fade_distance 120
}

light_source {
    <0,50,99>
    rgb 0.8
    area_light 10*x,10*y,5,5 adaptive 0 jitter circular orient
    fade_power 2
    fade_distance 100
}

#version 3.1;
camera {
    location <0,25,-40>
    right image_width/image_height*x
    look_at 5*y
    angle 20
    rotate 5*y
}

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> When simply using assumed_gamma 1, the results I get are wrong.

I fully agree. What's the catch in using gamma 1?  I have read about these
things but I don't see any benefit of stepping away from 2.2

Thanks for sharing the cloud code Rune!  :o)

Regards,
Hugo

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Rune wrote:
>
> When simply using assumed_gamma 1, the results I get are wrong.

The result is right, you just expect something else. Remember
that the monitor distorts your perception of the true relations
in the scene. Without assumed_gamma you are seeing a distorted
image.

When using assumed_gamma 1, one tends to build scenes with fixed
contrast ratio so they will look good without post processing.
This limits the scenes somewhat but no more than before. It will
train the eye to see the true relations in a scene, which is
valuable knowledge. It will enable you, with post processing, to
build scenes in a wide range of contrast ratios.


_____________
Kari Kivisalo

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