POV-Ray : Newsgroups : povray.advanced-users : Black spots in PR 3.6 radiosity Server Time
31 Oct 2024 23:32:47 EDT (-0400)
  Black spots in PR 3.6 radiosity (Message 1 to 7 of 7)  
From: jeroen de haan
Subject: Black spots in PR 3.6 radiosity
Date: 14 Sep 2004 15:27:27
Message: <4147461f$1@news.povray.org>
Hi all,

I have a problem with POV Ray 3.6 and radiosity. Random black spots appear
that aren't there when I render the same file in 3.5

Take a look at this file (PR 3.6)
http://www.brickshelf.com/gallery/jeroendehaan/Renders/povray360.jpg
and this (PR 3.5)
http://www.brickshelf.com/gallery/jeroendehaan/Renders/povray350.jpg

These are the radiosity settings:

 global_settings {
          max_trace_level 20
          radiosity {
            brightness 1
            count 300
            distance_maximum 100
            error_bound 0.25
            gray_threshold 0.50
            low_error_factor 0.775
            minimum_reuse 0.015
            nearest_count 8
            recursion_limit 1
          }
        }

and for the colours:

#declare lg_color_B00 = texture {
   pigment { rgbft <0, 0.0749999999999997, 0.9, 0, 0> }
   normal { bumps .01 scale .10 turbulence 0  }
   finish {
      ambient .0
      diffuse 1
      brilliance 1
      phong 1 phong_size 40
      specular 1
      reflection { .05 falloff 1 exponent 1 }
      conserve_energy
  }
}

This is for blue. All the colours use the same normal and finish.

Is it me, a wrong setting or a "bug" in 3.6?

Jeroen de Haan

If you want the complete file please e-mail me on infor at digitalbricks dot
nl


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From: Christoph Hormann
Subject: Re: Black spots in PR 3.6 radiosity
Date: 14 Sep 2004 15:40:03
Message: <ci7h7l$iqf$1@chho.imagico.de>
jeroen de haan wrote:
> Hi all,
> 
> I have a problem with POV Ray 3.6 and radiosity. Random black spots appear
> that aren't there when I render the same file in 3.5
> 

What makes you think this has anything to do with radiosity?

Apart from that a minimal test scene will of course be required to check 
this.

Christoph

-- 
POV-Ray tutorials, include files, Sim-POV,
HCR-Edit and more: http://www.tu-bs.de/~y0013390/
Last updated 06 Jul. 2004 _____./\/^>_*_<^\/\.______


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From: jeroen de haan
Subject: Re: Black spots in PR 3.6 radiosity
Date: 14 Sep 2004 16:31:24
Message: <4147551c@news.povray.org>
"Christoph Hormann" <chr### [at] gmxde> wrote in message
news:ci7h7l$iqf$1@chho.imagico.de...
> jeroen de haan wrote:
> > Hi all,
> >
> > I have a problem with POV Ray 3.6 and radiosity. Random black spots
appear
> > that aren't there when I render the same file in 3.5
> >
>
> What makes you think this has anything to do with radiosity?
>
> Apart from that a minimal test scene will of course be required to check
> this.

Here is a no radiosity test from PR 3.6:
http://www.brickshelf.com/gallery/jeroendehaan/Renders/kraanpovray36noradiosity.png

Jeroen


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From: Slime
Subject: Re: Black spots in PR 3.6 radiosity
Date: 14 Sep 2004 16:57:07
Message: <41475b23$1@news.povray.org>
A similar problem was mentioned by Michael Raiford on 6/13/2004 12:20 AM in
povray.binaries.images. I don't think a solution was found, though the
consensus seemed to be that it was related to media-radiosity interaction.

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


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From: Mike Raiford
Subject: Re: Black spots in PR 3.6 radiosity
Date: 15 Sep 2004 07:53:44
Message: <41482d48@news.povray.org>
Slime wrote:

> A similar problem was mentioned by Michael Raiford on 6/13/2004 12:20 AM in
> povray.binaries.images. I don't think a solution was found, though the
> consensus seemed to be that it was related to media-radiosity interaction.
> 
>  - Slime
>  [ http://www.slimeland.com/ ]

This seemed to happen in scenes that contained radiosity+scattering 
media+spotlights. At least for me, this is the situation I ran across.


-- 
~Mike


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From: Gilles Tran
Subject: Re: Black spots in PR 3.6 radiosity
Date: 15 Sep 2004 10:36:18
Message: <41485362$1@news.povray.org>

news:4147461f$1@news.povray.org...

>       reflection { .05 falloff 1 exponent 1 }

Could you try to remove the reflection statement (particularly the exponent)
to see if it works. It solved a vaguely similar problem for another user
(see the last messages in povray.beta-test.binaries). I came upon the
black-dots-in-radiosity-scene-issue myself (though I solved it eventually by
using another object as I was a little bit in a hurry...).

G.

-- 

**********************
http://www.oyonale.com
**********************
- Graphic experiments
- POV-Ray and Poser computer images
- Posters


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From: Christoph Hormann
Subject: Re: Black spots in PR 3.6 radiosity
Date: 15 Sep 2004 12:00:02
Message: <ci9onl$j52$1@chho.imagico.de>
Gilles Tran wrote:
> 
>>      reflection { .05 falloff 1 exponent 1 }
> 
> 
> Could you try to remove the reflection statement (particularly the exponent)
> to see if it works. It solved a vaguely similar problem for another user
> (see the last messages in povray.beta-test.binaries). I came upon the
> black-dots-in-radiosity-scene-issue myself (though I solved it eventually by
> using another object as I was a little bit in a hurry...).

Note the exponent is 1 which is default.  The bug report you cited had 
trouble with non-default just like the scene using crand Bob Hughes 
showed some time ago.  Apparently the changes made to prevent those 
problems did not completely slove it, the code applying the exponent 
should always check for the argument being below zero.  But i have never 
seen the same problem with exponent 1 (and if you have a scene showing 
this please post it).

Christoph

-- 
POV-Ray tutorials, include files, Sim-POV,
HCR-Edit and more: http://www.tu-bs.de/~y0013390/
Last updated 06 Jul. 2004 _____./\/^>_*_<^\/\.______


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