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From: Tek
Subject: wierd radiosity error
Date: 4 Mar 2004 01:42:54
Message: <4046cfee@news.povray.org>
I've not seen this one before. I have this simple scene with some coloured
blocks lying on a white floor, with a light source in one direction and
radiosity set to Radiosity_Final from rad_def.inc. As you can see the blocks
seem to cause an echo in the inverse of their colour, in the direction of the
light (as if somehow they'd reflected negative light!?)

Anybody seen this before? Have I done something crazy?

Source code available if anyone wants it.

-- 
Tek
www.evilsuperbrain.com


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From: Rafal 'Raf256' Maj
Subject: Re: wierd radiosity error
Date: 4 Mar 2004 03:00:15
Message: <Xns94A25B6E1D2D7raf256com@203.29.75.35>
tek### [at] evilsuperbraincom news:4046cfee@news.povray.org

> I've not seen this one before. I have this simple scene with some
> coloured blocks lying on a white floor, with a light source in one
> direction and radiosity set to Radiosity_Final from rad_def.inc. As
> you can see the blocks seem to cause an echo in the inverse of their
> colour, in the direction of the light (as if somehow they'd reflected
> negative light!?) 

Could You post full code (maybe in .b.scene


-- 
http://www.raf256.com/3d/
Rafal Maj 'Raf256', home page - http://www.raf256.com/me/
Computer Graphics


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From: Tek
Subject: Re: wierd radiosity error
Date: 4 Mar 2004 03:31:42
Message: <4046e96e$1@news.povray.org>
Done.

-- 
Tek
www.evilsuperbrain.com

"Rafal 'Raf256' Maj" <spa### [at] raf256com> wrote in message
news:Xns94A25B6E1D2D7raf256com@203.29.75.35...
> tek### [at] evilsuperbraincom news:4046cfee@news.povray.org
>
> > I've not seen this one before. I have this simple scene with some
> > coloured blocks lying on a white floor, with a light source in one
> > direction and radiosity set to Radiosity_Final from rad_def.inc. As
> > you can see the blocks seem to cause an echo in the inverse of their
> > colour, in the direction of the light (as if somehow they'd reflected
> > negative light!?)
>
> Could You post full code (maybe in .b.scene
>
>
> -- 
> http://www.raf256.com/3d/
> Rafal Maj 'Raf256', home page - http://www.raf256.com/me/
> Computer Graphics


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From: Rafal 'Raf256' Maj
Subject: Re: wierd radiosity error
Date: 4 Mar 2004 04:27:09
Message: <Xns94A26A29A2EC9raf256com@203.29.75.35>
tek### [at] evilsuperbraincom news:4046e96e$1@news.povray.org

> Done.

After a quick look, I would start with decreasing diffuse to 0.9 (1.0 diffuse does not
occure in nature, well at least in normal materials).

Maybe You would also try for example following radiosity settings:



#local QQ_RAD = 4; // <===== set this variable 0,1,2,3,4,5,6 or 7


#declare CFG_AMB = 0.3; // <==== set this variable for ambient when NOT using
radiosity

global_settings {      
  max_trace_level 20  
  
  assumed_gamma 1.4
  //assumed_gamma 2
  
  
  #if (QQ_RAD)           
    #declare CFG_AMB = 0;
    radiosity {  
      brightness 1  gray_threshold 0  max_sample 10 // <-- !
      #if (QQ_RAD=1) 
        normal on  pretrace_start 1/48  pretrace_end 1/256
        count 30  error_bound 0.90  low_error_factor 0.75
        adc_bailout 1/60  recursion_limit 3 minimum_reuse 1/96  nearest_count 5
      #end  
      #if (QQ_RAD=2) 
        normal on  pretrace_start 1/48  pretrace_end 1/256
        count 50  error_bound 0.80  low_error_factor 0.70
        adc_bailout 1/60  recursion_limit 4 minimum_reuse 1/96  nearest_count 6
      #end  
      #if (QQ_RAD=3) 
        normal on  pretrace_start 1/48  pretrace_end 1/256
        count 80  error_bound 0.60  low_error_factor 0.80
        adc_bailout 1/60  recursion_limit 4 minimum_reuse 1/96  nearest_count 6
      #end  
      #if (QQ_RAD=4) 
        normal on  pretrace_start 1/48  pretrace_end 1/256
        count 100  error_bound 0.50  low_error_factor 0.80
        adc_bailout 1/64  recursion_limit 4 minimum_reuse 1/256  nearest_count 7
      #end  
      #if (QQ_RAD=5)
        normal on  pretrace_start 1/64  pretrace_end 1/256
        count 200  error_bound 0.30  low_error_factor 0.80
        adc_bailout 1/64  recursion_limit 5 minimum_reuse 1/256  nearest_count 8
      #end  
      #if (QQ_RAD=6)
        normal on  pretrace_start 1/64  pretrace_end 1/256
        count 500  error_bound 0.23  low_error_factor 0.85
        adc_bailout 1/75  recursion_limit 6 minimum_reuse 1/256  nearest_count 8
      #end  
      #if (QQ_RAD=7)
        normal on  pretrace_start 1/64  pretrace_end 1/256
        count 1000  error_bound 0.17  low_error_factor 0.80
        adc_bailout 1/80  recursion_limit 7 minimum_reuse 1/256  nearest_count 10
      #end  
    }
  #end
}
default { 
  finish { ambient CFG_AMB } 
  pigment { rgb 1 }
}





-- 
http://www.raf256.com/3d/
Rafal Maj 'Raf256', home page - http://www.raf256.com/me/
Computer Graphics


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From: Tek
Subject: Re: wierd radiosity error
Date: 4 Mar 2004 04:33:39
Message: <4046f7f3$1@news.povray.org>
That's very interesting, and you make a good point about diffuse, but it doesn't
explain the artefacts!

I'm not interested in getting round the problem, that's easy! I want to know why
it happens.

-- 
Tek
www.evilsuperbrain.com


"Rafal 'Raf256' Maj" <spa### [at] raf256com> wrote in message
news:Xns94A26A29A2EC9raf256com@203.29.75.35...
> tek### [at] evilsuperbraincom news:4046e96e$1@news.povray.org
>
> > Done.
>
> After a quick look, I would start with decreasing diffuse to 0.9 (1.0 diffuse
does not occure in nature, well at least in normal materials).
>
> Maybe You would also try for example following radiosity settings:
>
>
>
> #local QQ_RAD = 4; // <===== set this variable 0,1,2,3,4,5,6 or 7
>
>
> #declare CFG_AMB = 0.3; // <==== set this variable for ambient when NOT using
radiosity
>
> global_settings {
>   max_trace_level 20
>
>   assumed_gamma 1.4
>   //assumed_gamma 2
>
>
>   #if (QQ_RAD)
>     #declare CFG_AMB = 0;
>     radiosity {
>       brightness 1  gray_threshold 0  max_sample 10 // <-- !
>       #if (QQ_RAD=1)
>         normal on  pretrace_start 1/48  pretrace_end 1/256
>         count 30  error_bound 0.90  low_error_factor 0.75
>         adc_bailout 1/60  recursion_limit 3 minimum_reuse 1/96  nearest_count
5
>       #end
>       #if (QQ_RAD=2)
>         normal on  pretrace_start 1/48  pretrace_end 1/256
>         count 50  error_bound 0.80  low_error_factor 0.70
>         adc_bailout 1/60  recursion_limit 4 minimum_reuse 1/96  nearest_count
6
>       #end
>       #if (QQ_RAD=3)
>         normal on  pretrace_start 1/48  pretrace_end 1/256
>         count 80  error_bound 0.60  low_error_factor 0.80
>         adc_bailout 1/60  recursion_limit 4 minimum_reuse 1/96  nearest_count
6
>       #end
>       #if (QQ_RAD=4)
>         normal on  pretrace_start 1/48  pretrace_end 1/256
>         count 100  error_bound 0.50  low_error_factor 0.80
>         adc_bailout 1/64  recursion_limit 4 minimum_reuse 1/256  nearest_count
7
>       #end
>       #if (QQ_RAD=5)
>         normal on  pretrace_start 1/64  pretrace_end 1/256
>         count 200  error_bound 0.30  low_error_factor 0.80
>         adc_bailout 1/64  recursion_limit 5 minimum_reuse 1/256  nearest_count
8
>       #end
>       #if (QQ_RAD=6)
>         normal on  pretrace_start 1/64  pretrace_end 1/256
>         count 500  error_bound 0.23  low_error_factor 0.85
>         adc_bailout 1/75  recursion_limit 6 minimum_reuse 1/256  nearest_count
8
>       #end
>       #if (QQ_RAD=7)
>         normal on  pretrace_start 1/64  pretrace_end 1/256
>         count 1000  error_bound 0.17  low_error_factor 0.80
>         adc_bailout 1/80  recursion_limit 7 minimum_reuse 1/256  nearest_count
10
>       #end
>     }
>   #end
> }
> default {
>   finish { ambient CFG_AMB }
>   pigment { rgb 1 }
> }
>
>
>
>
>
> -- 
> http://www.raf256.com/3d/
> Rafal Maj 'Raf256', home page - http://www.raf256.com/me/
> Computer Graphics


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From: Tim Cook
Subject: Re: wierd radiosity error
Date: 4 Mar 2004 13:26:03
Message: <404774bb@news.povray.org>
Tek wrote:
> Anybody seen this before? Have I done something crazy?

Crazy man, craaaaazy.  *thumbs up*


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From: Dan P
Subject: Re: wierd radiosity error
Date: 4 Mar 2004 23:40:48
Message: <404804d0$1@news.povray.org>
"Tek" <tek### [at] evilsuperbraincom> wrote in message
news:4046f7f3$1@news.povray.org...
> That's very interesting, and you make a good point about diffuse, but it
doesn't
> explain the artefacts!
>
> I'm not interested in getting round the problem, that's easy! I want to
know why
> it happens.

I'm interested in some learnin' on the whole Radiosity thing too. This is
the extent of my Radiosity knowledge:

* I go to the Special Effects menu.
* I insert the Radiosity effect.
* I boggle at most of the parameters.

That... that just isn't right. :-)


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From: Tek
Subject: Re: wierd radiosity error
Date: 5 Mar 2004 03:57:25
Message: <404840f5$1@news.povray.org>
> I'm interested in some learnin' on the whole Radiosity thing too. This is
> the extent of my Radiosity knowledge:
>
> * I go to the Special Effects menu.
> * I insert the Radiosity effect.
> * I boggle at most of the parameters.
>
> That... that just isn't right. :-)

Well I use the much simpler option:
#include "rad_def.inc"

global_settings{
    radiosity{ Rad_Settings(Radiosity_Fast,on,on) }
}

No nasty parameters there! You just decide what quality you want and off you go
:)

-- 
Tek
www.evilsuperbrain.com

"Dan P" <dan### [at] yahoocom> wrote in message
news:404804d0$1@news.povray.org...
> "Tek" <tek### [at] evilsuperbraincom> wrote in message
> news:4046f7f3$1@news.povray.org...
> > That's very interesting, and you make a good point about diffuse, but it
> doesn't
> > explain the artefacts!
> >
> > I'm not interested in getting round the problem, that's easy! I want to
> know why
> > it happens.
>
> I'm interested in some learnin' on the whole Radiosity thing too. This is
> the extent of my Radiosity knowledge:
>
> * I go to the Special Effects menu.
> * I insert the Radiosity effect.
> * I boggle at most of the parameters.
>
> That... that just isn't right. :-)
>
>


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From: Dan P
Subject: Re: wierd radiosity error
Date: 5 Mar 2004 17:23:10
Message: <4048fdce$1@news.povray.org>
"Tek" <tek### [at] evilsuperbraincom> wrote in message
news:404840f5$1@news.povray.org...
> > I'm interested in some learnin' on the whole Radiosity thing too. This
is
> > the extent of my Radiosity knowledge:
> >
> > * I go to the Special Effects menu.
> > * I insert the Radiosity effect.
> > * I boggle at most of the parameters.
> >
> > That... that just isn't right. :-)
>
> Well I use the much simpler option:
> #include "rad_def.inc"
>
> global_settings{
>     radiosity{ Rad_Settings(Radiosity_Fast,on,on) }
> }
>
> No nasty parameters there! You just decide what quality you want and off
you go
> :)

(I don't have POV here) -- is that a standard include? If so, awesome!


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From: Tek
Subject: Re: wierd radiosity error
Date: 5 Mar 2004 23:42:13
Message: <404956a5$1@news.povray.org>
"Dan P" <dan### [at] yahoocom> wrote in message
news:4048fdce$1@news.povray.org...
> > #include "rad_def.inc"
>
> (I don't have POV here) -- is that a standard include? If so, awesome!

Yup, it's one of the standard ones. It is truly awesome!

Back in the days of megapov I struggled to get radiosity set the way I wanted
it, and now these presets are higher quality and faster than the settings I used
to use!

-- 
Tek
www.evilsuperbrain.com


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