POV-Ray : Newsgroups : povray.newusers : sky_sphere and gradient Server Time
30 Jul 2024 18:12:10 EDT (-0400)
  sky_sphere and gradient (Message 1 to 7 of 7)  
From: Stefano Tessarin
Subject: sky_sphere and gradient
Date: 29 Sep 2003 10:57:07
Message: <3F784905.39BEFA2A@tin.it>
hi all!
i'm making a sky_sphere to look like a realistic sky, but the color
gradient it's very ugly!!

well the color combination is very realistic to me but instead of a
gradient it's a circulare scale even if I use radiosity, how can I avoid
this bad effect?

I took the colors using the dropper tool of Paint Shop Pro from an
actual picture of a late afternoon landscape.
this is the code:

sky_sphere   {
               pigment {gradient y
                        color_map { [0.0 color rgb <243,243,231>/255]
                                    [0.2 color rgb <212,212,219>/255]
                                    [0.25 color rgb <206,204,217>/255]
                                    [0.30 color rgb <200,197,224>/255]
                                    [0.35 color rgb <197,195,217>/255]
                                    [0.5 color rgb <178,178,228>/255]
                                    [1 color rgb <178,178,228>/255]
                                  }                        
                        }
     }

-- 
a presto, Stefano Tessarin:

-----> il primo portale del fermodellismo italiano
http://www.plasticando.com <------


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From: Christopher James Huff
Subject: Re: sky_sphere and gradient
Date: 29 Sep 2003 14:20:48
Message: <cjameshuff-F0F79D.14201429092003@netplex.aussie.org>
In article <3F784905.39BEFA2A@tin.it>,
 Stefano Tessarin <s.t### [at] tinit> wrote:

> well the color combination is very realistic to me but instead of a
> gradient it's a circulare scale even if I use radiosity, how can I avoid
> this bad effect?

Radiosity will not affect the appearance of the sky_sphere. The 
sky_sphere feature is a simple background effect, its color and pattern 
are what you specify for it.

I don't know what kind of effect you are trying to avoid...maybe you're 
seeing the horizon line where the gradient pattern repeats. The 
sky_sphere maps the pigment onto a sphere of unit radius, so it goes 
from y = -1 to y = 1. Your gradient pattern has two full gradients in 
that interval, and you see the line between them. You could flip your 
color_map upside down and use the planar pattern, or scale your gradient 
by 2 and translate downward by 1 to get it to fit the sky_sphere. (in 
this case, you would also have to adjust the color map, since half of it 
will be below the horizon)

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/


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From: Warp
Subject: Re: sky_sphere and gradient
Date: 29 Sep 2003 14:29:11
Message: <3f7879f7@news.povray.org>
Stefano Tessarin <s.t### [at] tinit> wrote:
> I took the colors using the dropper tool of Paint Shop Pro from an
> actual picture of a late afternoon landscape.

  Probably unrelated to your problem, but a small tip:

  If you do that, you might want to set #global_settings { assumed_gamma 1 }
at the beginning of your scene.

  I once wondered for hours why povray colors were completely different
from the ones I was seeing on my screen with another program. Then
it occurred to me that povray might be internally modifying the colors.

-- 
#macro N(D)#if(D>99)cylinder{M()#local D=div(D,104);M().5,2pigment{rgb M()}}
N(D)#end#end#macro M()<mod(D,13)-6mod(div(D,13)8)-3,10>#end blob{
N(11117333955)N(4254934330)N(3900569407)N(7382340)N(3358)N(970)}//  - Warp -


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From: Stefano Tessarin
Subject: Re: sky_sphere and gradient
Date: 29 Sep 2003 18:09:44
Message: <3F78AE66.2D56A3C7@tin.it>
> 
> I don't know what kind of effect you are trying to avoid...

instead of seeing a color gradient I see a series of color bands going
from the first color in the pattern to the last one. 

-- 
a presto, Stefano Tessarin:

-----> il primo portale del fermodellismo italiano
http://www.plasticando.com <------


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From: Christopher James Huff
Subject: Re: sky_sphere and gradient
Date: 29 Sep 2003 18:27:48
Message: <cjameshuff-4DF018.18272029092003@netplex.aussie.org>
In article <3F78AE66.2D56A3C7@tin.it>,
 Stefano Tessarin <s.t### [at] tinit> wrote:

> instead of seeing a color gradient I see a series of color bands going
> from the first color in the pattern to the last one. 

There is a band of bluer color in the gray area, removing the entry 
"[0.30 color rgb <200,197,224>/255]" fixes it. However, it blends 
smoothly. Are you sure you are viewing it at full color depth? Using 
thousands of colors will throw the colors off and cause banding in 
smooth gradients.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/


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From: Stefano Tessarin
Subject: Re: sky_sphere and gradient
Date: 30 Sep 2003 02:58:58
Message: <3F792A70.2E49BB7@tin.it>
Christopher James Huff wrote:

> There is a band of bluer color in the gray area, removing the entry
> "[0.30 color rgb <200,197,224>/255]" fixes it. However, it blends
> smoothly. 

thanks it works now!!!

>Are you sure you are viewing it at full color depth? Using

how could I know it?

-- 
a presto, Stefano Tessarin:

-----> il primo portale del fermodellismo italiano
http://www.plasticando.com <------


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From: Tom Melly
Subject: Re: sky_sphere and gradient
Date: 30 Sep 2003 04:54:49
Message: <3f7944d9$1@news.povray.org>
"Stefano Tessarin" <s.t### [at] tinit> wrote in message
news:3F7### [at] tinit...
>
> how could I know it?
>

Windows?

1. Everything you render will look 'orrible (banding, etc.)
2. Right-click on your desktop and select "properties", then take a look at the
settings tab - you should see that "colors" is set to either True Color or High
Color. If it's 256 colors or less, then you're not going to be seeing a proper
representation of your images (i.e. the actual image will have full color depth,
but you won't be able to see it).


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