POV-Ray : Newsgroups : povray.general : Radiosity and gamma Server Time
7 Aug 2024 05:15:27 EDT (-0400)
  Radiosity and gamma (Message 1 to 4 of 4)  
From: Peter Popov
Subject: Radiosity and gamma
Date: 29 Nov 2001 16:48:14
Message: <72bd0uc952vq18ufunekk8kua1o7f4vvmv@4ax.com>
Can anyone (Kari?) please summarize for me what were the sane settings
for a realistic radiosity render?

Right now I am using assumed_gamma 1.0 and Display_Gamma 2.3, output
to PNG (3.5 b7). Anything wrong with that?


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] vipbg
TAG      e-mail : pet### [at] tagpovrayorg


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From: Warp
Subject: Re: Radiosity and gamma
Date: 30 Nov 2001 08:48:08
Message: <3c078e18@news.povray.org>
Peter Popov <pet### [at] vipbg> wrote:
: Can anyone (Kari?) please summarize for me what were the sane settings
: for a realistic radiosity render?

  I don't think there is any fixed set of settings which will work with every
scene. You always have to fine-tune the setting in a per-scene basis.

-- 
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}//                     - Warp -


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From: Kari Kivisalo
Subject: Re: Radiosity and gamma
Date: 30 Nov 2001 13:46:22
Message: <3C07D40C.BE4364FC@engineer.com>
Peter Popov wrote:
> 
> Right now I am using assumed_gamma 1.0 and Display_Gamma 2.3, output
> to PNG (3.5 b7).

This will produce realistic representation of the scene on your display.
PNG in b7 is broken so some software may not display the image correctly.

The default values of brightness and gray_threshold are the correct ones
for the overall energy distribution so no need to touch those. The other
radiosity parameters can be tweked to remove artefacts, for speed/quality
control etc.

To produce the optimal image with these settings without post processing
you will have to design the scene and lighting so that the contrast ratio
is 1:10 to 1:100. Sounds complicated? It's not. Just design the scene
so that the preview looks good :) It's quite like what photographers do
in studio when shooting for media with limited contrast ratio, like
newspaper or magazine.

I would recommend sticking to the "assumed_gamma 1, don't touch
brightness or gray_threshold"-rule for beginners. When deviating
from this rule without knowing the exact reason you are just shooting
yourself in the foot :)


BTW, some time ago a Blender user wanted to know how povray can
render the Cornell reference so close to the original and what
settings were used. I sent him cornell.pov and he used RGB values
and other relevant setting from the pov file to produce this:
http://ourworld.compuserve.com/homepages/scorpius/blender_radiosity.htm
For some reason povray isn't mentioned on the page :)


_____________
Kari Kivisalo


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From: Peter Popov
Subject: Re: Radiosity and gamma
Date: 30 Nov 2001 17:07:02
Message: <of0g0u0gurelt53pdm2nm4jndsit05l1a8@4ax.com>
On Fri, 30 Nov 2001 20:46:36 +0200, Kari Kivisalo
<ray### [at] engineercom> wrote:

>I would recommend sticking to the "assumed_gamma 1, don't touch
>brightness or gray_threshold"-rule for beginners. When deviating
>from this rule without knowing the exact reason you are just shooting
>yourself in the foot :)

Thanks, Kari!


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] vipbg
TAG      e-mail : pet### [at] tagpovrayorg


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