Has anyone got a nice 3.5 file using media and photons that generates nice
ocean/swimming pool floor caustics?

I've been struggling for 3 days and I'm not really getting the results I want.
--
#macro A(V,B,C,R)#while(B-256)#if(V-128/B>=0)sphere{0,.5translate<C-4R-1,9>
pigment{rgb<1-C/8R/2C/8>}}#local V=V-128/B;#end#local B=B*2;#local C=C+1;#
end#end A(234,1,0,2)A(85,1,0,1)A(81,1,0,0)light_source{-5 1}//Tom Melly

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"Tom Melly" <tom### [at] tomandlucouk> wrote in message
news:3d8b1d18$1@news.povray.org...
> Has anyone got a nice 3.5 file using media and photons that generates nice
> ocean/swimming pool floor caustics?
>
> I've been struggling for 3 days and I'm not really getting the results I want.

Umm, possibly ignore this - I forgot C.Hormann's tutorial.

Chris - can you supply the pov-code you used to create:
http://www-public.tu-bs.de:8080/~y0013390/pov/water/water33_3b.jpg ?

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Tom Melly wrote:
> 
> [...]
> 
> Chris - can you supply the pov-code you used to create:
> http://www-public.tu-bs.de:8080/~y0013390/pov/water/water33_3b.jpg ?

The relevant code is:

global_settings {
   photons {
     spacing 0.003
   }
}
   
#declare M_Watx = 
material {
  texture {
    pigment {
      color rgbf 1
    }
    finish {
      diffuse 0.0
      ambient 0.0
       
      reflection {
        0.0, 1.0  
        fresnel on
      }

      conserve_energy

      specular 0.4 
      roughness 0.003
    }
    normal {
      bozo 
      scale 0.15 
    } 
  } 
  interior {
    ior 1.3
  }
} 
  

box { 
  <2.2,2.2,0>, <7.6,8,0>      
  material {
    M_Watx
  }  
  photons { target refraction on }
  hollow on
}

And in fact i would have expected you would be able to create something
similar after reading the tutorial - that's what it is for and nearly
every aspect of this code is handled in the text.

Christoph

-- 
POV-Ray tutorials, IsoWood include,                 
TransSkin and more: http://www.tu-bs.de/~y0013390/  
Last updated 13 Aug. 2002 _____./\/^>_*_<^\/\.______

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"Christoph Hormann" <chr### [at] gmxde> wrote in message
news:3D8B2DE9.2D0C3859@gmx.de...
>
>

> And in fact i would have expected you would be able to create something
> similar after reading the tutorial - that's what it is for and nearly
> every aspect of this code is handled in the text.
>

Ah - for some reason I thought that particular surface was a iso not just a
normal - I should have looked closer.

Actually I've realised the main problem I've been running into is too low a
photon count. I've switched to using spacing and am getting much better results.
I stupidly assumed that my lack of proper caustics was due to a bad function for
my water surface. Tchh.

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Tom Melly wrote:
> 
> Actually I've realised the main problem I've been running into is too low a
> photon count. I've switched to using spacing and am getting much better results.

FWIW and if I'm not mistaken, count and spacing are two ways of 
specifying the same thing; either way, X number of photons are 
generated, with the only difference being that count lets you set the 
number directly while spacing makes POV-Ray determine how many to 
generate (not as useful as it sounds, since AFAIK there's no way to 
reconcile spacing with any meaningful real-world value, and if you set 
spacing too large, POV-Ray won't generate enough photons anyway).

If there's some reason why spacing is better than count, someone please 
feel free to point it out...

That said, I find you generally need a LOT of photons to get good 
results. If you use count, try something above 100000, and adjust upward 
as needed.

-Xplo

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Xplo Eristotle wrote:
> 
> [...]
> 
> If there's some reason why spacing is better than count, someone please
> feel free to point it out...

The spacing is somehow proportional to how detailed the caustics are (not
precisely of course, this depends on the situation).  This means
specifying spacing is very useful if you shoot photons at a varying number
of objects, you get similar results then.  With a fixed count activating
photons on an additional object totally changes the outcome.

A disadvantage is of course you can't be sure in advance how many photons
will be shot.  Specifying too small spacing can easily lead to a several
hundred MB photons data and hours of parsing time - you have better
control over this aspect with count.

Christoph

-- 
POV-Ray tutorials, IsoWood include,                 
TransSkin and more: http://www.tu-bs.de/~y0013390/  
Last updated 13 Aug. 2002 _____./\/^>_*_<^\/\.______

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"Xplo Eristotle" <xpl### [at] infomagicnet> wrote in message
news:3d8c27fb$1@news.povray.org...

<snip>

See Christoph's reply, but basically I keep changing the size of the objects
involved with photons. Count then does not produce consistent results. Also,
with count, you have to often set a very high number, and somehow it's not as
easy to tweak, say, 10000000 as it is to tweak 0.2

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