Hi,
I have some questions about photons.

1) [ lame - booo :/ ] how can I get rid of that pure black, unrealistic 
shadow around nice photons caustics ? example :
http://www.raf256.com/pov/20020725phot/

2) is there some way to control brightness of photons ? maybe image will 
not be realistic but artistic effect would be imho nice

-- 
#macro g(U,V)(.4*abs(sin(9*sqrt(pow(x-U,2)+pow(y-V,2))))*pow(1-min(1,(sqrt(
pow(x-U,2)+pow(y-V,2))*.3)),2)+.9)#end#macro p(c)#if(c>1)#local l=mod(c,100
);g(2*div(l,10)-8,2*mod(l,10)-8)*p(div(c,100))#else 1#end#end light_source{
y 2}sphere{z*20 9pigment{function{p(26252423)*p(36455644)*p(66656463)}}}//M

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> 1) [ lame - booo :/ ] how can I get rid of that pure black, unrealistic
> shadow around nice photons caustics ? example :
> http://www.raf256.com/pov/20020725phot/

The pure black is, in fact, realistic. Any light coming into that spot
*would* be ambient light, so you should either use ambient or radiosity, or
maybe a shadowless light if you prefer, to make that spot lit. The idea is
that if the light is being refracted, and none of the photons are hitting
that spot, then why would it be lit? it wouldn't, except from ambient light.
Try reducing the ior, though, that may help spread the light out more to
fill the blackness some.

> 2) is there some way to control brightness of photons ? maybe image will
> not be realistic but artistic effect would be imho nice

1. Crank up the light source that casts photons and use save_file to save
the photon data. stop render after photon shooting finishes and rendering
starts.

2. Bring the light source back to normal and use load_file to load the
photon data for the final render.

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

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Slime <slm### [at] slimelandcom> wrote:
> Try reducing the ior, though, that may help spread the light out more to
> fill the blackness some.

  And make an unrealistic refraction? (IOR does not have effect only in
photons...)
  An area light (and photons shot from an area light) might be a better
solution (besides using a higher ambient, or even radiosity, of course).

-- 
#macro N(D)#if(D>99)cylinder{M()#local D=div(D,104);M().5,2pigment{rgb M()}}
N(D)#end#end#macro M()<mod(D,13)-6mod(div(D,13)8)-3,10>#end blob{
N(11117333955)N(4254934330)N(3900569407)N(7382340)N(3358)N(970)}//  - Warp -

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"Slime" <slm### [at] slimelandcom> wrote in news:3d40ace4@news.povray.org

>> 1) [ lame - booo :/ ] how can I get rid of that pure black,
>> unrealistic shadow around nice photons caustics ? example :
>> http://www.raf256.com/pov/20020725phot/
> The pure black is, in fact, realistic. Any light coming into that spot
> *would* be ambient light, so you should either use ambient or
> radiosity, or maybe a shadowless light if you prefer, to make that

yes now I see that :) I'll try to add radiosity in future to my scene

>> 2) is there some way to control brightness of photons ? maybe image
>> will not be realistic but artistic effect would be imho nice
> 1. Crank up the light source that casts photons and use save_file to
> save the photon data. stop render after photon shooting finishes and
> rendering starts.
> 2. Bring the light source back to normal and use load_file to load the
> photon data for the final render.

heh ;) good idea... but how about making this option a "normal" future of 
POV ? it's probalby very easy to implement. Besides this work around will 
not help if I have two object's and I want them to have diffrent photons 
power. How about :

we have a glass sphere, and white plane

sphere { ... photons { target refraction reflection } } 

plane {
  ...
  photons {   
    collect on
    power { ph_color, ph_effect }
  }
}

implementation :
color_final = (PHOTONS * ph_color)*ph_effect + (1-ph_effect)*COLOR

where :
we have pixel, that is placed in shadow of sphere, on plane.
PHOTONS - color of that pixel if photons are in use (plane collect photons)
COLOR - color of that pixel if photons where NOT used - collect off
and ofcourse color_final is the final color of that pixel

how about that ?
easy, simple and gives meany interesting possibilites :))

photons { ... power {1, 1} } 
photons { ... power {10, 1} } // very bright photons
photons { ... power {10, 1} } // very bright photons
photons { ... power {-1, 1} } // anty-photons - will dark scene :>>>
photons { ... power {1, 0.5} } // oject will be half with-photons and half 
without-photons - this is what I would use in my problem :
  http://www.raf256.com/pov/20020725phot/

What do You think ?

-- 
#macro g(U,V)(.4*abs(sin(9*sqrt(pow(x-U,2)+pow(y-V,2))))*pow(1-min(1,(sqrt(
pow(x-U,2)+pow(y-V,2))*.3)),2)+.9)#end#macro p(c)#if(c>1)#local l=mod(c,100
);g(2*div(l,10)-8,2*mod(l,10)-8)*p(div(c,100))#else 1#end#end light_source{
y 2}sphere{z*20 9pigment{function{p(26252423)*p(36455644)*p(66656463)}}}//M

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Warp <war### [at] tagpovrayorg> wrote in news:3d40bcaf@news.povray.org

> Slime <slm### [at] slimelandcom> wrote:
>> Try reducing the ior, though, that may help spread the light out more to
>> fill the blackness some.
>   And make an unrealistic refraction? (IOR does not have effect only in
> photons...)

sometimes  it is good to have artistic effect, even if it's not so photo-
realistic IMHO

>   An area light (and photons shot from an area light) might be a better
> solution (besides using a higher ambient, or even radiosity, of course).

I tryed area_light, but now I see I must use radiosity

-- 
#macro g(U,V)(.4*abs(sin(9*sqrt(pow(x-U,2)+pow(y-V,2))))*pow(1-min(1,(sqrt(
pow(x-U,2)+pow(y-V,2))*.3)),2)+.9)#end#macro p(c)#if(c>1)#local l=mod(c,100
);g(2*div(l,10)-8,2*mod(l,10)-8)*p(div(c,100))#else 1#end#end light_source{
y 2}sphere{z*20 9pigment{function{p(26252423)*p(36455644)*p(66656463)}}}//M

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"Rafal 'Raf256' Maj" <raf### [at] raf256com> wrote in
news:Xns### [at] 204213191226 

> photons { ... power {10, 1} } // very bright photons
> photons { ... power {-1, 1} } // anty-photons - will dark scene :>>>
> photons { ... power {1, 0.5} } // oject will be half with-photons and
> half without-photons 

and yes, I know that this is unrealistic ;)

-- 
#macro g(U,V)(.4*abs(sin(9*sqrt(pow(x-U,2)+pow(y-V,2))))*pow(1-min(1,(sqrt(
pow(x-U,2)+pow(y-V,2))*.3)),2)+.9)#end#macro p(c)#if(c>1)#local l=mod(c,100
);g(2*div(l,10)-8,2*mod(l,10)-8)*p(div(c,100))#else 1#end#end light_source{
y 2}sphere{z*20 9pigment{function{p(26252423)*p(36455644)*p(66656463)}}}//M

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