POV-Ray : Newsgroups : povray.general : Very thin material - how to avoid color changes? : Re: Very thin material - how to avoid color changes? Server Time
9 Dec 2024 09:17:24 EST (-0500)
  Re: Very thin material - how to avoid color changes?  
From: Alain Martel
Date: 30 Oct 2024 08:41:29
Message: <67222979$1@news.povray.org>
Le 2024-10-28 à 05:59, spigor a écrit :

> I also use:
> global_settings{
>      assumed_gamma 1
>      radiosity{
>          pretrace_start 1
>          pretrace_end 1
>          count 400
>          recursion_limit 1
>          nearest_count 1
>          error_bound 0.05
>      }
> }

That radiosity block make me twitch.
pretrace_start and pretrace_end 1 are only to be used for the last pass 
of multipass rendering when all of the radiosity data have been saved 
from a previous pass.
Even the default of 0.08 and 0.01 are to large. Using pretrace_end 
0.0025 or less tend to give better result, and is often faster overall 
as more, and better, data are collected during pretrace.

count is OK. Using the two value version will often improve the quality 
at nearly zero cost.
count 400, 1111

error_bound is acceptable for a scene using only radiosity illumination. 
If you use conventional light, then the default of 0.5 is sufficient.

nearest_count 1 will often cause artifacts. Better to use the adaptive 
version : nearest_count 20, 3


You should NOT use diffuse 1. It can cause some nasty side effect. 
Better keep the default value.
So, change that #default to just :
#default{finish{ambient 0}}

And use emission 1 in the finish block to create some light emitting object.


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