Try these photon settings:

        photons{
                gather 40, 100
                radius 0.3*phd, 1  // increased radius decreases
splotchiness
                autostop 1.5
                jitter .9  // jitter helps remove that lines effect
                expand_thresholds 0.2, 40
                range_divider 1000 // there must be a bug... but this is a
work-around for now
                adc_bailout 1/(256*40)
        }

To greatly decrease trace time, add
 photons { reflection off refraction off}
to your ambient light source.  You can take it off again for the final,
high-quality, trace once all testing is done, if you so desire.

-Nathan

Simen Kvaal <sim### [at] studentmatnatuiono> wrote in message
news:37ff302a@news.povray.org...
> I've created a test image with UVPOV using Photon Mapping. It is an
> illustration of a standard class-room experiment showing refraction and
> reflection. I wanted to see whether Photon mapping actually could do this,
> and the results were quite surprising.
>
> The only problem is that the rays are a bit splotchy and I cannot find
good
> settings for them.
>
> It was amazing to see that the photons are refracted through the prism and
> reflected on the inside, creating a zig-zag pattern as one would expect
from
> the real world. Rendering time was about 8 mins; 6 mins mapping photons.
:/
>
> But I am not quite happy yet. There seems to be some strange phenomena,
for
> example the forst refracted the stripe suddenly ends!
>
> Any comments welcome!
>
> Simen.
>
> ------
>
> // beginnig of source for prism1.jpg
>
> #include "colors.inc"
>
> // settings for photon gathering; as in example in the docs. Lower
> // phd gives better results and longer tracing time.
>
> #declare phd=0.35;
>
al_settings{  
>         photons{    
>                 gather 20, 100
>                 radius 0.1*phd, 2, 0.1*phd    
>                 file://autostop 0    
>                 jitter .01
>                 expand_threshol
ds 0.2, 40
>         }
>         max_trace_level 20
> }
>
>
> // an ambient light source
> light_source { <-50, 50, -50> color White*0.45 }
>
> // camera - placed on the z-axis then rotated
> camera {
>         location -z*30
>         direction z
>         up y
>         right 4/3*x
>         angle 40
>         look_at 0
>
>         rotate <47, 30, 0>
> }
>
>
> // some settings:
> #declare w = 0.41; // witdh of constraining container
> #declare l = 30; // length of containter - bigger gives narrower spreading
angle on the ray
> #declare stre = 10; // strenth of light - do not increase this if l is
increased - automatic adjustment here
> #declare h = 10; // height of container. Just a formality
>
> union {
>         light_source {
>                 <0, 2, 0> color White*l*stre
>         }
>
>
>                 difference {
>
>   box { <-(w/2+0.5), 0, -(w/2+0.5)>, <l,  h+1, w/2+0.5> }
>                         box { <-(w/2),    -1, -(w/2)>,     <l+1, h+2,
> w/2> }
>                         pigment {
>                                 color Green
>                         }
>                 }
>         translate x*-l
>         rotate y*70
>         translate <-7, 0, 15>
>
> }
>
>
> // the prism
>
> box {
>         -1, 1
>         scale <5, 1, 3>
>         translate y*1
>         pigment {
>                 color rgbf <1, 1, 1, 0.78>
>         }
>         finish {
>                 phong 1
>                 phong_size 150
>                 reflection 0.22
>                 ambient 0.4
>                 diffuse 0.6
>         }
>         interior {
>                 ior 1.44
>         }
>         photons {
>                 separation 0.02*phd
>                 refraction on
>                 reflection on
>                 file://ignore_photons
>   }
> }
>
>
>
>
> // graph paper
> plane {
>         y, 0
>         texture {
>                 pigment {
>                         gradient x
>                         color_map {
>                                 [0.0, 0.021 color Blue color Blue]
>                                 [0.021, 1.0 color White color White]
>                         }
>                 }
>         }
>
>         texture {
>                 pigment {
>                         gradient z
>                         color_map {
>                                 [0.0, 0.021 color Blue color Blue]
>                                 [0.021, 1.0 color Clear color Clear]
>                         }
>                 }
>
>
>                 finish {
>                         ambient 0.01
>                         diffuse 0.99
>                 }
>         }
>
> }
>
> // end of source.
>
>
>
>

Post a reply to this message