POV-Ray : Newsgroups : povray.newusers : Emitting media : Re: Emitting media Server Time
28 Mar 2024 20:26:52 EDT (-0400)
  Re: Emitting media  
From: Alain
Date: 1 Sep 2017 19:24:12
Message: <59a9ec1c@news.povray.org>
Le 17-08-31 à 18:58, Loren a écrit :
> Hello,
> 
> I'm having great difficult getting emitting media (glowing red media, as in a
> laser), in my scenes. First, a simple example which doesn't work:
> 
> 
> -------------
> // #include "shapes.inc"
> // #include "colors.inc"
> //
> // camera {
> // location 10
> // look_at 0
> //  angle 45
> // }
> // light_source { 10
> //  color rgb<1, 1, 1> }
> // sphere { 0, 1 color rgb<1,0,0> }
> 
> #include "colors.inc"
> 
> background { color White }
Emissive media can't show against a white background. Try something MUCH 
darker.
background { Cyant/5 }
or
background { Black }

> 
> camera {
>    location <0, 2, -3>
>    look_at <0, 1, 2>
> }
> 
> sphere {
>    <0, 1, 2>, 2
>    texture {
>      pigment { color rgbf 1 }
>    }
>    hollow
>    interior{
>         media{ emission Red intervals 30 samples 100,100 }
Yuck! That WAS ok in version 3.5 and older that used sampling method 2 
as the default. As of version 3.6, the sampling method is method 3 and 
it must use intervals 1 (the default value).
Using method 3, more intervals only dramatically slow you down. It can 
also cause some artefacts.
Also :
1) It only use a single value for samples. If a second value is used, 
it's silently ignored.
2) confidance and variance are also silently ignored as they are 
meaningless when you have only a single interval.

Use :
media{ emission Red samples 100 }

>    }
> }
> 
> light_source { <2, 4, -3> color White}
> 

Defaults for media in version 3.6+
method 3
samples 10
confidance Not Applicable
variance N/A
intervals 1
jitter 1

Alain


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