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From: Bald Eagle
Subject: Re: Steam Fog: First WIP
Date: 25 Feb 2019 16:55:01
Message: <web.5c74640268f7cc2a765e06870@news.povray.org>
MichaelJF <mi-### [at] t-onlinede> wrote:


> Rendering time was a little bit longer (3 weeks).

Eek.

What's the black circle in the lower left part of the render?

This is a great rising steam / mist effect  :)   You should do a mug of hot
coffee or something as a smaller test render.  :D

I see where you're going with the blurred background - but it looks... flat.
I'm not sure if adding a wee bit of emission to it would help, or switching the
palette from rgb to srgb, or changing the gamma would help...

But for a test render, 1. you have the patience of a saint and 2. it's looking
really good


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From: And
Subject: Re: Steam Fog: First WIP
Date: 25 Feb 2019 23:15:01
Message: <web.5c74bce568f7cc2a218a64860@news.povray.org>
MichaelJF <mi-### [at] t-onlinede> wrote:
> Am 25.02.2019 um 12:15 schrieb And:
> > MichaelJF <mi-### [at] t-onlinede> wrote:
> >> Hi to the crowd,
> >>
> >> this image has still a lot of flaws (sun colour and reflections, the
> >> swan model itself, textures of the cattails) and may be limitations to
> >> media by POV. media seems to be handling color_maps or density_maps
> >> different than pigment or texture having no interpolation between the
> >> map entries but shap edges. This is what I derived in a first attempt.
> >> Rendering time was a little bit longer (3 weeks).
> >>
> >> Best regards
> >> Michael
> >
> > Your light source don't look like from your sun
> >
> Hi And,
> thanks. I was not clear enough. This is the first flaw I mentioned. To
> be exact: sun colour and the colour of the emitting media doesn't match
> so far. More or less, in this WIP the sun is just a dummy to hint at my
> final intention.
>
> Best regards
> Michael

Uh huh, do you know how I'm aware of the problem? Because the tree is not with
its back to the light.


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From: Thomas de Groot
Subject: Re: Steam Fog: First WIP
Date: 26 Feb 2019 05:15:36
Message: <5c7511c8@news.povray.org>
On 24-2-2019 20:20, MichaelJF wrote:
> Hi Thomas,
> this time a didn't click accidentally into the image while converting it 
> to jpg with the GIMP, but with purpose. In the marked area you can see 
> the sharp edges I mean. The code was
> 
> #if(SteamFog)
>     #declare DensBoden1= density {
>        agate
>        agate_turb 1
>        density_map {
>           [ 0 rgb <1,1,1>/5 ]
>           //[ 0.02 rgb <1,1,1> ]
>           [ 0.03 rgb <0,0,0> ]
>           [ 1 rgb <0,0,0> ]
>        }
>     }
> 
>     #declare DensBoden3= density {
>        agate
>        agate_turb 1
>        density_map {
>           [ 0 rgb <1,1,1>/5 ]
>           //[ 0.02 rgb <1,1,1> ]
>           [ 0.02 rgb <0,0,0> ]
>           [ 1 rgb <0,0,0> ]
>        }
>        scale <5,50,5>
>        //warp { turbulence <0.5,0.1,0.5> }
>        //rotate <0,90,0>
>     }
> 
>     #declare DensLuft = density {
>        rgb <0,0,0>
>     }
>     box { <-150,0.001,-15>,<150.01,1,150> pigment { rgbt 1 } hollow
>        interior {
>           media {
>              scattering { 2, White/5 }
>              //absorption <0,0.25,1>
>              //intervals 25
>              samples 64
>              density {
>                 gradient y
>                 density_map {
>                    [ 0 DensBoden1 ]
>                    [ 0.5 DensBoden1 ]
>                    [ 0.6 DensLuft ]
>                    [ 1 DensLuft ]
>                 }
>                 scale <1,2,1> translate <0,-0.5,0> // avoid repetition

> at height 1
>                 warp { turbulence <0.01,0.4,0.01> }
>              }
>           }
>           media {
>              scattering { 2, White/5 }
>              //absorption <0,0.25,1>
>              //intervals 25
>              samples 64
>              density {
>                 gradient y
>                 density_map {
>                    [ 0 DensBoden3 ]
>                    [ 0.5 DensBoden3 ]
>                    [ 0.6 DensLuft ]
>                    [ 1 DensLuft ]
>                 }
>                 scale <1,2,1> translate <0,-0.5,0> // avoid repetition

> at height 1
>                 warp { turbulence <0.01,0.3,0.01> }
>              }
>           }
>           #if(GlobalFog)
>              media { scattering {2, White/5 } density { rgb 0.001 } }
>           #end
>        }
>     }
>     #if(GlobalFog)
>        box { <-100,1.001,-5.9>,<100,25,130> pigment { rgbt 1} hollow
>           interior {
>              media { scattering {2, White/5 } density { rgb 0.0001 } }
>           }
>        }
>     #end
> #end
> 
> GlobalFog was activated. May be I have overlooked some thing or the other.
> 

My first tests of your code confirms me that the sharp edge is the 
result of the container boundary, not of any different behaviour of density.

I want to test different options yet.

-- 
Thomas


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From: MichaelJF
Subject: Re: Steam Fog: First WIP
Date: 26 Feb 2019 13:12:31
Message: <5c75818f$1@news.povray.org>
Am 26.02.2019 um 05:13 schrieb And:
> MichaelJF <mi-### [at] t-onlinede> wrote:
>> Am 25.02.2019 um 12:15 schrieb And:
>>> MichaelJF <mi-### [at] t-onlinede> wrote:
>>>> Hi to the crowd,
>>>>
>>>> this image has still a lot of flaws (sun colour and reflections, the
>>>> swan model itself, textures of the cattails) and may be limitations to
>>>> media by POV. media seems to be handling color_maps or density_maps
>>>> different than pigment or texture having no interpolation between the
>>>> map entries but shap edges. This is what I derived in a first attempt.
>>>> Rendering time was a little bit longer (3 weeks).
>>>>
>>>> Best regards
>>>> Michael
>>>
>>> Your light source don't look like from your sun
>>>
>> Hi And,
>> thanks. I was not clear enough. This is the first flaw I mentioned. To
>> be exact: sun colour and the colour of the emitting media doesn't match
>> so far. More or less, in this WIP the sun is just a dummy to hint at my
>> final intention.
>>
>> Best regards
>> Michael
> 
> Uh huh, do you know how I'm aware of the problem? Because the tree is not with
> its back to the light.
> 
Hi And,
there are only two light_sources within the scene. The emitting media 
representing the sun and a second miles behind it, but in the same 
direction (in front of the camera). The backside illumination of the 
trees comes from the reflections of the overall present scattering media 
and the use of radiosity.

Best regards
Michael


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From: MichaelJF
Subject: Re: Steam Fog: First WIP
Date: 26 Feb 2019 13:22:32
Message: <5c7583e8$1@news.povray.org>
Am 25.02.2019 um 22:54 schrieb Bald Eagle:
> MichaelJF <mi-### [at] t-onlinede> wrote:
> 
> 
>> Rendering time was a little bit longer (3 weeks).
> 
> Eek.
> 
> What's the black circle in the lower left part of the render?
> 
> This is a great rising steam / mist effect  :)   You should do a mug of hot
> coffee or something as a smaller test render.  :D
> 
> I see where you're going with the blurred background - but it looks... flat.
> I'm not sure if adding a wee bit of emission to it would help, or switching the
> palette from rgb to srgb, or changing the gamma would help...
> 
> But for a test render, 1. you have the patience of a saint and 2. it's looking
> really good
> 
Thanks Bald Eagle,
the black spot is an accident while convertig the image to jpg with the 
GIMP. I accidentally clicked into the image with an active pen and 
noticed it after the posting.

I will look at my mug tomorrow, but I think it is a steam different to 
the one I observed at the moselle last may completely. Anyway, this 
would not solve the issue with the rendering time, because the media 
will scale with the scene.

Best regards
Michael


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From: jr
Subject: Re: Steam Fog: First WIP
Date: 26 Feb 2019 13:35:00
Message: <web.5c7585d068f7cc2abcd610c90@news.povray.org>
hi,

MichaelJF <mi-### [at] t-onlinede> wrote:
> Hi to the crowd,
> this image has still a lot of flaws (sun colour and reflections, the
> swan model itself, textures of the cattails) and may be limitations to
> media by POV. media seems to be handling color_maps or density_maps
> different than pigment or texture having no interpolation between the
> map entries but shap edges. This is what I derived in a first attempt.
> Rendering time was a little bit longer (3 weeks).

as has been said already, that is _some_ image in the making.  (almost expected
a mansion at the end of the "boating lake" :-)).

agree that the (sun) colour isn't quite right, too .. vibrant, the overall
"feel" is too warm to expect to see vapour rising into cool/colder air.  also,
still just IMO, the sun is a touch high.


regards, jr.


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From: MichaelJF
Subject: Re: Steam Fog: First WIP
Date: 26 Feb 2019 13:48:41
Message: <5c758a09$1@news.povray.org>
Am 26.02.2019 um 11:15 schrieb Thomas de Groot:
> On 24-2-2019 20:20, MichaelJF wrote:
>> Hi Thomas,
>> this time a didn't click accidentally into the image while converting 
>> it to jpg with the GIMP, but with purpose. In the marked area you can 
>> see the sharp edges I mean. The code was
>>
>> #if(SteamFog)
>>     #declare DensBoden1= density {
>>        agate
>>        agate_turb 1
>>        density_map {
>>           [ 0 rgb <1,1,1>/5 ]
>>           //[ 0.02 rgb <1,1,1> ]
>>           [ 0.03 rgb <0,0,0> ]
>>           [ 1 rgb <0,0,0> ]
>>        }
>>     }
>>
>>     #declare DensBoden3= density {
>>        agate
>>        agate_turb 1
>>        density_map {
>>           [ 0 rgb <1,1,1>/5 ]
>>           //[ 0.02 rgb <1,1,1> ]
>>           [ 0.02 rgb <0,0,0> ]
>>           [ 1 rgb <0,0,0> ]
>>        }
>>        scale <5,50,5>
>>        //warp { turbulence <0.5,0.1,0.5> }
>>        //rotate <0,90,0>
>>     }
>>
>>     #declare DensLuft = density {
>>        rgb <0,0,0>
>>     }
>>     box { <-150,0.001,-15>,<150.01,1,150> pigment { rgbt 1 } hollow
>>        interior {
>>           media {
>>              scattering { 2, White/5 }
>>              //absorption <0,0.25,1>
>>              //intervals 25
>>              samples 64
>>              density {
>>                 gradient y
>>                 density_map {
>>                    [ 0 DensBoden1 ]
>>                    [ 0.5 DensBoden1 ]
>>                    [ 0.6 DensLuft ]
>>                    [ 1 DensLuft ]
>>                 }
>>                 scale <1,2,1> translate <0,-0.5,0> // avoid
repetition 
>> at height 1
>>                 warp { turbulence <0.01,0.4,0.01> }
>>              }
>>           }
>>           media {
>>              scattering { 2, White/5 }
>>              //absorption <0,0.25,1>
>>              //intervals 25
>>              samples 64
>>              density {
>>                 gradient y
>>                 density_map {
>>                    [ 0 DensBoden3 ]
>>                    [ 0.5 DensBoden3 ]
>>                    [ 0.6 DensLuft ]
>>                    [ 1 DensLuft ]
>>                 }
>>                 scale <1,2,1> translate <0,-0.5,0> // avoid
repetition 
>> at height 1
>>                 warp { turbulence <0.01,0.3,0.01> }
>>              }
>>           }
>>           #if(GlobalFog)
>>              media { scattering {2, White/5 } density { rgb 0.001 } }
>>           #end
>>        }
>>     }
>>     #if(GlobalFog)
>>        box { <-100,1.001,-5.9>,<100,25,130> pigment { rgbt 1} hollow
>>           interior {
>>              media { scattering {2, White/5 } density { rgb 0.0001 } }
>>           }
>>        }
>>     #end
>> #end
>>
>> GlobalFog was activated. May be I have overlooked some thing or the 
>> other.
>>
> 
> My first tests of your code confirms me that the sharp edge is the 
> result of the container boundary, not of any different behaviour of 
> density.
> 
> I want to test different options yet.
> 
Hm,
the problem seems to be within the second media statement (the first 
produces some ground noise only). The container boundary is at level y=1 
(y is up here). The transition between DensBoden3 and DensLuft(=nothing) 
is between 0.5 and 0.6 scaled to 1 and 1.2 but then translated to 0.5 
and 0.7 which is beneath the container boundary for sure.

Many thanks
Michael


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From: Thomas de Groot
Subject: Re: Steam Fog: First WIP
Date: 27 Feb 2019 02:24:01
Message: <5c763b11$1@news.povray.org>
On 26-2-2019 19:48, MichaelJF wrote:
> Am 26.02.2019 um 11:15 schrieb Thomas de Groot:
>> On 24-2-2019 20:20, MichaelJF wrote:
>>> Hi Thomas,
>>> this time a didn't click accidentally into the image while converting 
>>> it to jpg with the GIMP, but with purpose. In the marked area you can 
>>> see the sharp edges I mean. The code was
>>>
>>> #if(SteamFog)
>>>     #declare DensBoden1= density {
>>>        agate
>>>        agate_turb 1
>>>        density_map {
>>>           [ 0 rgb <1,1,1>/5 ]
>>>           //[ 0.02 rgb <1,1,1> ]
>>>           [ 0.03 rgb <0,0,0> ]
>>>           [ 1 rgb <0,0,0> ]
>>>        }
>>>     }
>>>
>>>     #declare DensBoden3= density {
>>>        agate
>>>        agate_turb 1
>>>        density_map {
>>>           [ 0 rgb <1,1,1>/5 ]
>>>           //[ 0.02 rgb <1,1,1> ]
>>>           [ 0.02 rgb <0,0,0> ]
>>>           [ 1 rgb <0,0,0> ]
>>>        }
>>>        scale <5,50,5>
>>>        //warp { turbulence <0.5,0.1,0.5> }
>>>        //rotate <0,90,0>
>>>     }
>>>
>>>     #declare DensLuft = density {
>>>        rgb <0,0,0>
>>>     }
>>>     box { <-150,0.001,-15>,<150.01,1,150> pigment { rgbt 1 } hollow
>>>        interior {
>>>           media {
>>>              scattering { 2, White/5 }
>>>              //absorption <0,0.25,1>
>>>              //intervals 25
>>>              samples 64
>>>              density {
>>>                 gradient y
>>>                 density_map {
>>>                    [ 0 DensBoden1 ]
>>>                    [ 0.5 DensBoden1 ]
>>>                    [ 0.6 DensLuft ]
>>>                    [ 1 DensLuft ]
>>>                 }
>>>                 scale <1,2,1> translate <0,-0.5,0> // avoid 
>>> repetition at height 1
>>>                 warp { turbulence <0.01,0.4,0.01> }
>>>              }
>>>           }
>>>           media {
>>>              scattering { 2, White/5 }
>>>              //absorption <0,0.25,1>
>>>              //intervals 25
>>>              samples 64
>>>              density {
>>>                 gradient y
>>>                 density_map {
>>>                    [ 0 DensBoden3 ]
>>>                    [ 0.5 DensBoden3 ]
>>>                    [ 0.6 DensLuft ]
>>>                    [ 1 DensLuft ]
>>>                 }
>>>                 scale <1,2,1> translate <0,-0.5,0> // avoid 
>>> repetition at height 1
>>>                 warp { turbulence <0.01,0.3,0.01> }
>>>              }
>>>           }
>>>           #if(GlobalFog)
>>>              media { scattering {2, White/5 } density { rgb 0.001 } }
>>>           #end
>>>        }
>>>     }
>>>     #if(GlobalFog)
>>>        box { <-100,1.001,-5.9>,<100,25,130> pigment { rgbt 1} hollow
>>>           interior {
>>>              media { scattering {2, White/5 } density { rgb 0.0001 } }
>>>           }
>>>        }
>>>     #end
>>> #end
>>>
>>> GlobalFog was activated. May be I have overlooked some thing or the 
>>> other.
>>>
>>
>> My first tests of your code confirms me that the sharp edge is the 
>> result of the container boundary, not of any different behaviour of 
>> density.
>>
>> I want to test different options yet.
>>
> Hm,
> the problem seems to be within the second media statement (the first 
> produces some ground noise only). The container boundary is at level y=1 
> (y is up here). The transition between DensBoden3 and DensLuft(=nothing) 
> is between 0.5 and 0.6 scaled to 1 and 1.2 but then translated to 0.5 
> and 0.7 which is beneath the container boundary for sure.
> 

I have yet to test the second media I confess. ;-)

Something interesting to do [hint] is to put the density scale /after/ 
the warp{turbulence}. Makes things a bit complicated but worth the 
experiment.
-- 
Thomas


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From: Thomas de Groot
Subject: Re: Steam Fog: First WIP
Date: 27 Feb 2019 03:10:11
Message: <5c7645e3@news.povray.org>
On 26-2-2019 19:48, MichaelJF wrote:

> Hm,
> the problem seems to be within the second media statement (the first 
> produces some ground noise only). The container boundary is at level y=1 
> (y is up here). The transition between DensBoden3 and DensLuft(=nothing) 
> is between 0.5 and 0.6 scaled to 1 and 1.2 but then translated to 0.5 
> and 0.7 which is beneath the container boundary for sure.
> 

Ok. I think I got it. The solution seems to be really simple. In both 
media's density maps change:

         density_map {
           [ 0 DensBoden1 ]
           [ 0.45 DensBoden1 ]  //original: 0.5
           [ 0.55 DensLuft ]    //original: 0.6
           [ 1 DensLuft ]
         }

         density_map {
           [ 0 DensBoden3 ]
           [ 0.45 DensBoden3 ]  //original: 0.5
           [ 0.55 DensLuft ]    //original: 0.6
           [ 1 DensLuft ]
         }

That is all. If you want to increase the diffuseness, you can always 
increase the distance between the two values, e.g. 0.35 --> 0.55. But I 
would advise not to go higher than approximately 0.55.

-- 
Thomas


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From: Thomas de Groot
Subject: Re: Steam Fog: First WIP
Date: 27 Feb 2019 03:55:07
Message: <5c76506b@news.povray.org>
A small test image with the corrected settings. What appears to be the 
horizon is in reality the semitransparent bounding box, the camera being 
situated just a tiny bit above it. The mist strands do not touch that 
upper boundary but be aware that their extension upward is controlled by 
the warp{turbulence} of 0.4 for the y-direction. So, it is a bit tricky 
to find the correct values for the density map without the strands 
piercing the container.

Samples may be a bit low as there are some artifacts visible but I 
wouldn't change it as in your scene they would be hidden by the water 
texture.

I have used here a somewhat denser scattering colour and also scattering 
mode 5 which I often prefer, here with excentricity 0.5.

For this small scene, render time was about 30 minutes.

-- 
Thomas


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Attachments:
Download 'media mist_test.png' (245 KB)

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media mist_test.png


 

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