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29 Jul 2024 06:22:10 EDT (-0400)
  A common lamp light_source... (Message 1 to 5 of 5)  
From: Gyscos
Subject: A common lamp light_source...
Date: 29 Apr 2006 09:50:00
Message: <web.44536ed8e10211fa1ba56a630@news.povray.org>
Hello (again, again...) !!
This time it's a common lamp i'm building.
A made a glass half-sphere and put a light_source inside, but the light
source is really strong and illuminate the street outside the house, and
the others houses lol O_o

So i tried fade_distance and fade_power, but I'd be really glad if someone
could tell me about wich values I should use to make somehing realistic...
I'm using 1 unit for 1 meter, and the lamp is a common lamp... to light a
whole room but not MUCH more...


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From: Warp
Subject: Re: A common lamp light_source...
Date: 29 Apr 2006 10:09:17
Message: <4453738d@news.povray.org>
Gyscos <gys### [at] gmailcom> wrote:
> So i tried fade_distance and fade_power, but I'd be really glad if someone
> could tell me about wich values I should use to make somehing realistic...
> I'm using 1 unit for 1 meter, and the lamp is a common lamp... to light a
> whole room but not MUCH more...

  Just use fade_power 2 and tune fade_distance until it looks good.

  There's no "correct" value for fade_distance because that depends on
the brightness of the lamp in the first place. Just tune it until the
scene looks good.

-- 
                                                          - Warp


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From: Gyscos
Subject: Re: A common lamp light_source...
Date: 29 Apr 2006 11:30:01
Message: <web.4453862c5897c9e61ba56a630@news.povray.org>
Okay...
The doc said something about a new way of calculating one the fade_power
reached 1000, i thought that meant I had to use much higher value than just
1 or 2...
Thanks !


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From: Alain
Subject: Re: A common lamp light_source...
Date: 29 Apr 2006 12:36:47
Message: <4453961f$1@news.povray.org>
Gyscos nous apporta ses lumieres en ce 29/04/2006 11:28:
> Okay...
> The doc said something about a new way of calculating one the fade_power
> reached 1000, i thought that meant I had to use much higher value than just
> 1 or 2...
> Thanks !
> 
> 
The fade_power you mention here is for the fading in the interior of object, NOT
light_source.

You may effectively need to use high rgb values for your lamp. It all depend on the
proportions 
between your scene distances ant the fade_distance. If tou want "nominal" illumination
at a distance 
of 1 and you have a fade_distance of 0.1 (10 cm), you need to multiply the light
intensity by 100, 
if fade_distance is 0.01 (1 cm), you need 10000* the "nominal" value.
Normal, physicaly exact, fade_power is 2. A fade_power of 1 can be used to simulate a
very long and 
narrow light_source.

-- 
Alain
-------------------------------------------------
Agnostic #2: Did someone shit?


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From: Warp
Subject: Re: A common lamp light_source...
Date: 29 Apr 2006 15:28:41
Message: <4453be66@news.povray.org>
Gyscos <gys### [at] gmailcom> wrote:
> The doc said something about a new way of calculating one the fade_power
> reached 1000, i thought that meant I had to use much higher value than just
> 1 or 2...

  As said, the fade_power 1000 is only effective in interior fading, and
unfortunately that "1000" is not a true value but just a hack which got
into the official povray (a keyword would have been much better). Don't
think about it as the value "1000" in this context because it isn't.

-- 
                                                          - Warp


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