POV-Ray : Newsgroups : povray.advanced-users : Lumens in LightSysIV? : Re: Lumens in LightSysIV? Server Time
24 May 2024 19:47:26 EDT (-0400)
  Re: Lumens in LightSysIV?  
From: Alain
Date: 12 Jun 2019 13:25:46
Message: <5d01359a$1@news.povray.org>
Le 19-06-11 à 21:32, Mike Horvath a écrit :
> What is the correct method of calculating and specifying Lumens in 
> LightSysIV?
> 
>      Light_Color(light_temp, light_lumens)
> 
> Do I need to know the distance and diameter of the Sun beforehand? What 
> about fade_power and fade_distance?
> 
> Thanks.
> 
> 
> Michael

For the Sun, don't bother with light fading : Use a light with the 
parallel option and you are good. Unless your scene scale is 
interplanetary, the fading over the extent of your scene is totally 
negligible.

For the extent of the Sun when using an area_light, make it's diameter 
about 0.01 of the distance. Not exact, but close enough.

For more normal lights, the fade_power must be 2. No other value is 
realistic.

For fade_distance : Make it small. For an area_light, it should be about 
the width of the light. For point light, a value of about 0.1 is correct.


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