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From: Lsq
Subject: Help:how to build underwater images
Date: 24 Mar 2016 09:50:01
Message: <web.56f3eff8f12d35403fdf54d50@news.povray.org>
Hi,

A freshman.I would like to build some underwater images with several objects and
it seems that there is water in the images.Where can I get some simple examples?
Thanks!


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From: Koppi
Subject: Re: Help:how to build underwater images
Date: 24 Mar 2016 10:35:00
Message: <web.56f3fabf7cad1731db8f4ad50@news.povray.org>
'Rays' by Jeff Reifel - http://paulbourke.net/exhibition/scc5/final.html


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From: Norbert Kern
Subject: Re: Help:how to build underwater images
Date: 24 Mar 2016 11:20:01
Message: <web.56f404ab7cad1731c9c86f150@news.povray.org>
"Lsq" <285### [at] qqcom> wrote:
> Hi,
>
> A freshman.I would like to build some underwater images with several objects and
> it seems that there is water in the images.Where can I get some simple examples?
> Thanks!

Some underwater scenes with sources worth looking at -

http://news.povray.org/povray.binaries.scene-files/thread/%3C455c0b4b$1@news.povray.org%3E/

http://news.povray.org/povray.binaries.images/message/%3C3D21F7DD.5030007%40bellsouth.net%3E/#%3C3D21F7DD.5030007%40bel
lsouth.net%3E

http://news.povray.org/povray.binaries.images/message/%3Cweb.510c1a6a1927e6d96eb3cf340%40news.povray.org%3E/#%3Cweb.510
c1a6a1927e6d96eb3cf340%40news.povray.org%3E

http://news.povray.org/povray.general/message/%3C3e1ecc5f%40news.povray.org%3E/#%3C3e1ecc5f%40news.povray.org%3E

http://www.povcomp.com/entries/161.php (faked lightbeams)

Norbert


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From: Koppi
Subject: Re: Help:how to build underwater images
Date: 24 Mar 2016 11:40:01
Message: <web.56f409277cad1731db8f4ad50@news.povray.org>
A study of caustics light and an introduction to POV-Ray with source code:
http://asiber.ifs.hr/bruno_pauns_caustic/BrunoPaun_diplomski_rad.pdf


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From: Alain
Subject: Re: Help:how to build underwater images
Date: 24 Mar 2016 14:11:32
Message: <56f42dd4@news.povray.org>

> Hi,
>
> A freshman.I would like to build some underwater images with several objects and
> it seems that there is water in the images.Where can I get some simple examples?
> Thanks!
>
>

Water seriously limit how far yopu can se things. With that in mind, the 
following features, and how to use them, will come handy:

Colour fading. This will make the colour of what you see fade toward 
some value. It's an attribute of the interior of objects.
To use it you need to encase your scene into a large object with a hole 
at the camera location:
difference{
box{-10000, 10000 pigment{rgbt 1}interior{fade_colour<0.1, 0.3, 
0.8>fade_distance 100 fade_power 1001}
hollow // this allow the use of fog and media
}
sphere{Camera_location 0.1 pigment{rgbt 1}}
}
This render fast but don't show any caustics of rays of light.


You can fill your scene with scattering media:

box{-10000, 10000 pigment{rgbt 1}
interior{
media{
  scattering{2, <0.1, 0.3, 0.8>
  }
}
sphere{Camera_location 0.1 pigment{rgbt 1}}
hollow // required to allow media to exist
}

Using media is slower.
Scattering medis will make lights visible.
To get beleiveable results, you need to use fading lights as follow:
light_source{
	Location, rgb Light_colour*1000
	fade_power 2 fade_distance 0.1
}

The light's intensity must be large as it fades rapidly with the 
distance. If the light is not bright enough, increase the intensity. The 
fade_distance need to be short to beheave realisticaly and fade_power 2 
is the only physicaly accurate value that you can use.
If you want to use the area_light feature, you can set fade_distance to 
the dimention of the area_light or to zero and use area_illumination.

Colour fading and media are compatible and can be used at the same time 
in the same area.

Finaly, you can use fog.
fog is a fast and dirty approximation of scattering media that never 
interact with the lights.
I don't recomend using fog except as a "place holder" for the media 
while devloping your scene.


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From: Lsq
Subject: Re: Help:how to build underwater images
Date: 24 Mar 2016 23:30:00
Message: <web.56f4b0877cad17313fdf54d50@news.povray.org>
"Koppi" <jak### [at] gmailcom> wrote:
> 'Rays' by Jeff Reifel - http://paulbourke.net/exhibition/scc5/final.html
Hi Koppi,I have a question about Jeff Reifel's code and the code is following:
// Entry code: mpszaw
// Name      : Jeff Reifel
// Frame rate: 10
#local C=clock*pi;
#macro
 B(N,F)        // blob elements for wings and tail
 sphere{0,F/7,1
 scale 1-pow(I.5)
 translate-I*F*x
 rotate y*N*90
 rotate-N*x*pow(5,I)*10*sin(I*2-C*8+i) // shapes and flaps wings
 scale.2+x*.8
 translate-x}
 #end
 #local i=C;
 #while(i<2*pi+C) // spaces and moves rays
 #local I=0;
 blob{
 #while(I<1)
 B(1,7)  // wing
 B(-1,7) //wing
 B(0,3)  // tail
 #local I=I+.01;
 #end
 rotate<-90,cos(i*3)*-45,i*pi*36> //orients ray on knot
 translate<sin(i)+2*sin(2*i),5+cos(i)-2*cos(2*i),3*sin(3*i)+7>*2   //knot
 rotate x*37
 pigment{slope y}}
 #local i=i+pi/8;
 #end
 light_source{<0,60,99> 1 spotlight}
 media{
 intervals 6
 scattering{
 2
 rgb<0.1,0.2,1>/99}
 }


question:I cannot find the keyword camera{}in the source code,can you tell me
which codes act as the function of camera? Thanks!


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From: tth
Subject: Re: Help:how to build underwater images
Date: 25 Mar 2016 03:21:50
Message: <56f4e70e$1@news.povray.org>
On 03/25/2016 04:29 AM, Lsq a dit:

>
> question:I cannot find the keyword camera{}in the source code,can you tell me
> which codes act as the function of camera? Thanks!

    Camera default values ?
    http://www.povray.org/documentation/3.7.0/r3_4.html#r3_4_2



-- 
http://weblog.mixart-myrys.org/?post/2016/02/THSF-V7


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From: Alain
Subject: Re: Help:how to build underwater images
Date: 25 Mar 2016 13:34:26
Message: <56f576a2$1@news.povray.org>


>
> question:I cannot find the keyword camera{}in the source code,can you tell me
> which codes act as the function of camera? Thanks!
>
>
If you don't define a camera, there is a default camera that will be 
used. It's defined as follow:

camera{
  perspective
  location<0,0,0>
  up y
  sky y
  right 1.33*x
  direction z
  look_at z
}


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From: Bald Eagle
Subject: Re: Help:how to build underwater images
Date: 25 Mar 2016 14:15:01
Message: <web.56f57f207cad17315e7df57c0@news.povray.org>
First trick for writing short code:

http://paulbourke.net/exhibition/scc4/hints.txt

Also search the newsgroups for short code examples and tricks, and study some of
the short-code SDL signatures people have posted.


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From: LanuHum
Subject: Re: Help:how to build underwater images
Date: 25 Mar 2016 19:15:00
Message: <web.56f5c5917cad17317a3e03fe0@news.povray.org>
"Bald Eagle" <cre### [at] netscapenet> wrote:
> First trick for writing short code:
>
> http://paulbourke.net/exhibition/scc4/hints.txt
>
> Also search the newsgroups for short code examples and tricks, and study some of
> the short-code SDL signatures people have posted.

http://news.povray.org/povray.binaries.images/message/%3Cweb.56f5c393dec2fd427a3e03fe0%40news.povray.org%3E/#%3Cweb.56f
5c393dec2fd427a3e03fe0%40news.povray.org%3E


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