POV-Ray : Newsgroups : povray.general : underwater media help! Server Time
5 May 2024 09:00:18 EDT (-0400)
  underwater media help! (Message 1 to 8 of 8)  
From: Mike Williams
Subject: underwater media help!
Date: 9 Jan 2003 23:34:18
Message: <3e1e4d4a@news.povray.org>
I am trying to setup a scene underwater. I am not yet good with media. Does
anyone have ideas how to make a good underwater media?

thanks


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From: Slime
Subject: Re: underwater media help!
Date: 10 Jan 2003 01:21:00
Message: <3e1e664c$1@news.povray.org>
> I am trying to setup a scene underwater. I am not yet good with media.
Does
> anyone have ideas how to make a good underwater media?


My most successful attempt was
http://www.slimeland.com/images/pictures/realwater.jpg. Some hints:

1. use scattering media with a low density. Start with a grey color before
trying colored water. I had best results with scattering type 5, after
fiddling with the eccentricity value.
2. if you want the light-beams effect, don't use media photons - use faked
caustics. the final appearance is incredibly similar.
3. dont try anything fancy (like the light-beams) until you've gotten used
to estimating a good number of samples. The larger the body of water (the
longer the distance to the back of it), the more samples you'll need.

 - Slime
[ http://www.slimeland.com/ ]


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From: Timothy R  Cook
Subject: Re: underwater media help!
Date: 10 Jan 2003 02:07:23
Message: <3e1e712b@news.povray.org>
Mike Williams wrote:
> I am trying to setup a scene underwater. I am not yet good with media. Does
> anyone have ideas how to make a good underwater media?

I've found that using low media sample of 1 often produces adequate
results, where 2 or 3 give blotchy results, not looking decent until
samples ot 20...and sample of 1 is a lot quicker ;)
also I habitually use confidence of 0.0001 and variance of 1.

to get underwater sun-beams, make a large hollow box, place camera
within.  place a light source external to the box, put a sphere with
a turbulent pattern of your choice varying from opaque to transmit 1
around that light.  this gives a nice texture on the surface of the
water, and beams of light.  for water colour, try a fade distance
appropriate to scene, and a blue emission colour.

-- 
--Tim Cook
http://empyrean.scifi-fantasy.com

-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GFA dpu- s: a?-- C++(++++) U P? L E--- W++(+++)>$
N++ o? K- w(+) O? M-(--) V? PS+(+++) PE(--) Y(--)
PGP-(--) t* 5++>+++++ X+ R* tv+ b++(+++) DI
D++(---) G(++) e*>++ h+ !r--- !y--
------END GEEK CODE BLOCK------


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From: lieven ke
Subject: Re: underwater media help!
Date: 10 Jan 2003 04:45:05
Message: <web.3e1e94c4bb4e9f3a34cdce030@news.povray.org>
Timothy R. Cook wrote:
>Mike Williams wrote:
>> I am trying to setup a scene underwater. I am not yet good with media. Does
>> anyone have ideas how to make a good underwater media?

There is also the "Gille Tran's submarine" in "advanced scenes" file of
POV3.5.

Tommy


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From: Tom Melly
Subject: Re: underwater media help!
Date: 10 Jan 2003 08:36:31
Message: <3e1ecc5f@news.povray.org>
"Mike Williams" <mic### [at] quixnetnet> wrote in message
news:3e1e4d4a@news.povray.org...
> I am trying to setup a scene underwater. I am not yet good with media. Does
> anyone have ideas how to make a good underwater media?
>
> thanks
>

Here's where I got to with this...

#version 3.5;

#include "colors.inc"
#include "functions.inc"

#declare Photon_sp    = 0.2; //.2
#declare Cont_rad     = 35; // 35
#declare Sea_col      = <1,1,1,1>; //<0.5,0.9,1.0,1.0>;
#declare Sea_medcol   = <0.8,0.2,0.1>*0.75; // 0.75
#declare Dens_min     = 0.1;//.1
#declare Cam_z        = -15;

#declare Do_sea       = true;

#if(abs(Cam_z)+10>(Cont_rad))
  Camera too far away!
#end

global_settings {
  assumed_gamma 1.0
  ambient_light 0
  photons{
    spacing Photon_sp
    autostop 0 jitter 0.4
    media 100
    save_file "seabed.ph"
    //load_file "seabed.ph"
  }
}

#declare Dens_func = function(x,y,z){min(1,Dens_min + pow(x/(Cont_rad),2) +
pow(z/(Cont_rad),2))}

#declare Sea_media =
media{
  method 3
  intervals 10
  samples 3,15
  scattering {1,0.025 extinction 0.8} //0.025  0.8
  absorption Sea_medcol
  density{function{Dens_func(x,y,z)}}
}


// ----------------------------------------

camera {
  location  <0.0, 0.0, Cam_z>
  look_at   <0.0, -5.0, 35>
}

sky_sphere {
  pigment {
    wrinkles scale 0.25
    color_map {
      [0.0 rgb <0.6,0.7,1.0>]
      [0.7 rgb <0.2,0.4,0.8>]
    }
  }
}

light_source {
  <0, 0, 0>
  color rgb <1, 1, 1>*5
  media_interaction on
  media_attenuation on
  fade_distance 1500
  fade_power 2
  translate <1000, 2000, -500>
}

// ----------------------------------------

#declare Bed_func = function(x,y,z){
  y +
  5 +
  (sin(x*5 - sin(z + f_noise3d(x,0,z))*1)/20) -
  (sin((x+z)*1 -
  sin(z + f_noise3d(x,0,z))*1)/30)
}

#declare Bed_base =
difference{
  isosurface {
    function { Bed_func(x, y, z) }
    contained_by {sphere{0,Cont_rad}}
    accuracy 0.001
    max_gradient 2
    rotate y*35
  }
  plane{z,Cam_z-10}
  pigment{rgb<0.9,0.9,0.6>}
}

#declare Sea_func = function(x,y,z){y - 5}

#declare Sea_top =
difference{
  isosurface{
    function { Sea_func(x*1, y*1, z*1) }
    contained_by {sphere{0,Cont_rad}}
    accuracy 0.001
    max_gradient 5
    rotate y*25
  }
  plane{z,Cam_z-10}

  pigment{rgbf Sea_col}

  normal{bozo 5 scale 1/4}

  hollow
  photons{target refraction on reflection on}
  finish{
    reflection{fresnel on}
    ambient 0 diffuse 0 conserve_energy
  }
  interior{
    ior 1.34
    media{Sea_media}
  }
}

#declare Wall =
difference{
  sphere{0,Cont_rad}
  sphere{0,Cont_rad - 0.01}
  plane{y,-7}
  plane{-y,-7.5}
  plane{z,Cam_z-10}
  pigment{rgb 0}
  photons{collect off}
}

object{Bed_base}
object{Sea_top}
object{Wall}


sphere{
  0,4
  scale <1,1.5,1>
  pigment{rgb 0.5}
  normal{agate scale 10}
  normal{granite scale 1/4}
  translate <0,-3,0>
}


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From: Mike Williams
Subject: Re: underwater media help!
Date: 10 Jan 2003 13:25:01
Message: <3e1f0ffd@news.povray.org>
I plan on posting what i have already found then i will apply some of these
great comments and see what i can create.

Besides i thought it would help to have an idea of the scene i was trying to
do.


"Mike Williams" <mic### [at] quixnetnet> wrote in message
news:3e1e4d4a@news.povray.org...
> I am trying to setup a scene underwater. I am not yet good with media.
Does
> anyone have ideas how to make a good underwater media?
>
> thanks
>
>


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From: gonzo
Subject: Re: underwater media help!
Date: 10 Jan 2003 14:05:06
Message: <web.3e1f1861bb4e9f3aa0c272b50@news.povray.org>
Slime wrote:

>My most successful attempt was
>http://www.slimeland.com/images/pictures/realwater.jpg. >


Hey, that water looks good! But a tip, (from someone who spends a LOT of
time underwater) the bubbles are all wrong... Only the smallest bubbles are
spherical. As the bubbles rise to the surface and expand, they flatten out
to a flying saucer shape. (and break into smaller bubbles around the edges
so they appear in clusters, almost never see single bubbles)

RG - they told me in school they were preparing me for the real world... so
now I've graduated to the real world, what happened to recess?


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From: Slime
Subject: Re: underwater media help!
Date: 10 Jan 2003 18:44:20
Message: <3e1f5ad4$1@news.povray.org>
> Hey, that water looks good! But a tip, (from someone who spends a LOT of
> time underwater) the bubbles are all wrong... Only the smallest bubbles
are
> spherical. As the bubbles rise to the surface and expand, they flatten out
> to a flying saucer shape. (and break into smaller bubbles around the edges
> so they appear in clusters, almost never see single bubbles)

Haha, you're not the first person to say that =)

 - Slime
[ http://www.slimeland.com/ ]


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