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From: Sven Littkowski
Subject: Distant Haze - How To?
Date: 31 Mar 2018 10:49:14
Message: <5abf67aa@news.povray.org>
Hi, please have a look to the attached photo. It shows, here from orbit,
the distant haze at the horizon that makes the horizon line less visible.

I am working on my 1850s Mississippi Paddle-Wheel Steamboat, and need
such a horizon-affecting distant haze, too. But i tried ground fog and
regular fog already, and did not achieve the desired effect.

Does anyone of us POV-Ray community citizens have some tricks that can
do that? Maybe a huge torus with some sort of media in it? That would be
my guess (I however have almost no clue how to create media). Doing it
at the moment with Photoshop only...


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Attachments:
Download 'button_titan_110km.jpg' (11 KB)
Download 'sl - mississippi paddle-wheel steamer - prow - side.jpg' (530 KB)

Preview of image 'button_titan_110km.jpg'
button_titan_110km.jpg

Preview of image 'sl - mississippi paddle-wheel steamer - prow - side.jpg'
sl - mississippi paddle-wheel steamer - prow - side.jpg


 

From: Alain
Subject: Re: Distant Haze - How To?
Date: 31 Mar 2018 16:24:17
Message: <5abfb631$1@news.povray.org>
Le 18-03-31 à 06:49, Sven Littkowski a écrit :
> Hi, please have a look to the attached photo. It shows, here from orbit,
> the distant haze at the horizon that makes the horizon line less visible.
> 
> I am working on my 1850s Mississippi Paddle-Wheel Steamboat, and need
> such a horizon-affecting distant haze, too. But i tried ground fog and
> regular fog already, and did not achieve the desired effect.
> 
> Does anyone of us POV-Ray community citizens have some tricks that can
> do that? Maybe a huge torus with some sort of media in it? That would be
> my guess (I however have almost no clue how to create media). Doing it
> at the moment with Photoshop only...
> 
> 
> ---
> Diese E-Mail wurde von AVG auf Viren geprüft.
> http://www.avg.com
> 

Using fog, you probably need to increase the distance parameter.

Otherwise, I'd use some atmospheric scattering media using the mie_haze 
or mie_murky model. You need to use a low density. A sample count of 3 
to 5 should be enough.

Don't forget to provide some actual back plane behind that fog or media. 
It can be a simple plane with pigment{rgbt 1}.


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From: Sven Littkowski
Subject: Re: Distant Haze - How To?
Date: 31 Mar 2018 17:53:23
Message: <5abfcb13$1@news.povray.org>
Thanks. But would atmospheric scattering media not be hazy to all
directions? I still want to see the deep-blue sky (sphere), just at the
horizon i want to have that blurred stripe of hazy distance haze.

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From: Sven Littkowski
Subject: Re: Distant Haze - How To?
Date: 31 Mar 2018 17:54:01
Message: <5abfcb39$1@news.povray.org>
Thanks. But would atmospheric scattering media not be hazy to all
directions? I still want to see the deep-blue sky (sphere), just at the
horizon i want to have that blurred stripe of hazy distance haze.

I still give a try, always curious. :-D

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From: clipka
Subject: Re: Distant Haze - How To?
Date: 31 Mar 2018 18:30:50
Message: <5abfd3da@news.povray.org>
Am 31.03.2018 um 19:53 schrieb Sven Littkowski:
> Thanks. But would atmospheric scattering media not be hazy to all
> directions? I still want to see the deep-blue sky (sphere), just at the
> horizon i want to have that blurred stripe of hazy distance haze.

For realistic results, I alwasy recommend to consider reality:

In reality, the reason why the haze is only visible toward the horizon
is because the atmosphere gets less dense as you go up.

So that's exactly what I'd do with the media.

(I'd use two different media, one just for the blue with density
corresponding to atmospheric density to model some clear air, and
another one more strongly confined to lower altitudes for a white-ish
hazy air. For the blue component, Rayleigh scattering should be used
because that's what happens in the atmosphere, and for the white-ish
component one of the haze scattering modes is probbably best suited,
modelling larger dirt particles.)


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From: Thomas de Groot
Subject: Re: Distant Haze - How To?
Date: 1 Apr 2018 07:03:46
Message: <5ac08452$1@news.povray.org>
You could try this code, changing the colours of the media of course to 
white or very light grey.

//start code
#local SkyScale = 100;

#local Density_out =
density {
   bozo  //agate
   density_map {
     [0.2 rgb 1.0]
     [0.5 rgb 0.2]
     [0.8 rgb 1.0]
   }
   scale 0.05 //0.1
   warp {turbulence <0.5 0.4, 0.5>*2}
}

#local MistSphere =
difference {
   sphere { <0, 0, 0>, 1}
   plane {-y, 0 translate 10/SkyScale*y}
   texture {pigment {rgb 0 transmit 1} }
   hollow
   interior {
     media {
       intervals 1
       absorption <0.10, 0.10, 0.12>
       scattering {1, rgb <1, 1, 0.8>*1.4/SkyScale}
       samples 50
       confidence 0.9999
       variance 1/1000
       ratio 0.9
       density {
         spherical
         density_map {
           [0.880 Density_out]
           [0.960 rgb 0]
         }
       }
     }
   }
   scale SkyScale
   translate CamLoc
}

MistSphere
//end code

-- 
Thomas


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From: Sven Littkowski
Subject: Re: Distant Haze - How To?
Date: 25 Apr 2018 18:25:28
Message: <5ae0c818$1@news.povray.org>
Working with this feature now, trying to make some changes. I need the
haze at the horizon, but not too much higher than it. Changing the
spherical density map to a gradient density map, maybe that can do the
trick.

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From: Sven Littkowski
Subject: Re: Distant Haze - How To?
Date: 26 Apr 2018 16:15:53
Message: <5ae1fb39@news.povray.org>
Okay, for the amusement, I am posting now some of my results of creating
a "horizon haze". Not finish yet, but the first results are from ...
some other dimension (the image with the black fragments).

The second image shows ground fog, but the disadvantage here is that
this fog makes the water whitish with its own light color. Is there a
way to cut away any part of the ground fog that is below -0.75?


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Attachments:
Download 'horizon haze - 01.jpg' (96 KB)
Download 'horizon haze - 02.jpg' (47 KB)

Preview of image 'horizon haze - 01.jpg'
horizon haze - 01.jpg

Preview of image 'horizon haze - 02.jpg'
horizon haze - 02.jpg


 

From: clipka
Subject: Re: Distant Haze - How To?
Date: 26 Apr 2018 16:29:43
Message: <5ae1fe77$1@news.povray.org>
Am 26.04.2018 um 18:15 schrieb Sven Littkowski:
> Okay, for the amusement, I am posting now some of my results of creating
> a "horizon haze". Not finish yet, but the first results are from ...
> some other dimension (the image with the black fragments).
> 
> The second image shows ground fog, but the disadvantage here is that
> this fog makes the water whitish with its own light color. Is there a
> way to cut away any part of the ground fog that is below -0.75?

IIRC you can set up "negative" ground fog to counteract the positive one.


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From: Thomas de Groot
Subject: Re: Distant Haze - How To?
Date: 27 Apr 2018 07:42:46
Message: <5ae2d476$1@news.povray.org>
The following has worked fairly well for me in the past. Tweak, by all 
means!

#declare NearFogColor = <0.799, 0.799, 0.80>*1.2; //Blueish color
#declare FarFogColor  = <0.90, 0.90, 0.90>; //Light gray horizon color

//Near fog
fog {distance 4000 fog_type 2 fog_offset 25 fog_alt 20 color srgb 
NearFogColor}

//Distant fog
fog {distance 8000 fog_type 2 fog_offset 25 fog_alt 20 color srgb 
FarFogColor-NearFogColor}



-- 
Thomas


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