POV-Ray : Newsgroups : povray.advanced-users : LightSys looks_like? Server Time
26 Jun 2024 08:13:23 EDT (-0400)
  LightSys looks_like? (Message 1 to 6 of 6)  
From: SharkD
Subject: LightSys looks_like?
Date: 4 Jun 2010 04:53:50
Message: <4c08bf1e$1@news.povray.org>
Is there a command to make a LightSys light source like a CSG object? I 
haven't discovered one yet but am assuming one was created.

Thanks!


Mike


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From: SharkD
Subject: Re: LightSys looks_like?
Date: 4 Jun 2010 05:10:50
Message: <4c08c31a$1@news.povray.org>
On 6/4/2010 4:53 AM, SharkD wrote:
> Is there a command to make a LightSys light source like a CSG object? I
> haven't discovered one yet but am assuming one was created.
>
> Thanks!
>
>
> Mike

Also, what is the proper way to scale the Lumens parameter of a light 
source?

Let's say you are modeling the sun, and in your scene the sun is A units 
away. How do I decrease/increase lumens to match?


Mike


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From: Alain
Subject: Re: LightSys looks_like?
Date: 4 Jun 2010 12:02:48
Message: <4c0923a8@news.povray.org>
Le 2010-06-04 05:10, SharkD a écrit :
> On 6/4/2010 4:53 AM, SharkD wrote:
>> Is there a command to make a LightSys light source like a CSG object? I
>> haven't discovered one yet but am assuming one was created.
>>
>> Thanks!
>>
>>
>> Mike
>
> Also, what is the proper way to scale the Lumens parameter of a light
> source?
>
> Let's say you are modeling the sun, and in your scene the sun is A units
> away. How do I decrease/increase lumens to match?
>
>
> Mike

If the light is non-fading, there is no need to scale it's parameters 
other than it's distance.

If you use an area_light, you need to adjust it's size relative to it's 
distance if you want to keep the same penumbrae. Scale the size by the 
same value as the distance.

Whenever you have a fading light_source, you can scale the fading using 
fade_distance.
Another option is to change the intensity of the light itself.

With fade_power 2, if you put the light twice farther, you can ether 
double the fade_distance and keep the same intensity OR quadruple the 
intensity and keep the same fade_distance.

NEVER use multiple coincident lights. It uselessly increase the 
rendering time.



Alain


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From: SharkD
Subject: Re: LightSys looks_like?
Date: 4 Jun 2010 15:46:32
Message: <4c095818@news.povray.org>
On 6/4/2010 12:02 PM, Alain wrote:
> If the light is non-fading, there is no need to scale it's parameters
> other than it's distance.
>
> If you use an area_light, you need to adjust it's size relative to it's
> distance if you want to keep the same penumbrae. Scale the size by the
> same value as the distance.
>
> Whenever you have a fading light_source, you can scale the fading using
> fade_distance.
> Another option is to change the intensity of the light itself.
>
> With fade_power 2, if you put the light twice farther, you can ether
> double the fade_distance and keep the same intensity OR quadruple the
> intensity and keep the same fade_distance.
>
> NEVER use multiple coincident lights. It uselessly increase the
> rendering time.
>
>
>
> Alain


I don't think the light uses fade_distance, thanks.

-- 
http://isometricland.com


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From: Jaime Vives Piqueres
Subject: Re: LightSys looks_like?
Date: 5 Jun 2010 03:33:35
Message: <4c09fdcf$1@news.povray.org>
El 04/06/10 11:10, SharkD escribió:
> On 6/4/2010 4:53 AM, SharkD wrote:
>> Is there a command to make a LightSys light source like a CSG object?
>> I haven't discovered one yet but am assuming one was created.

   No, but you can just attach anything using looks_like. For example, on the
demo_outdoor scene, you can modify the sun light to this:

light_source{
  SolarPosition
  Light_Color(SunColor,6)
  looks_like{...}
}

> Also, what is the proper way to scale the Lumens parameter of a light
> source?
>
> Let's say you are modeling the sun, and in your scene the sun is A units
>  away. How do I decrease/increase lumens to match?

   Unfortunately, the Skylight model included in Lightsys doesn't take care
of this... you have to set it arbitrarily. Lumens in Lightsys are just a way
to allow setting proportional intensities between different lights in the
same scene. So, if you only have a sun light, just set the Lumens to some
amount that lights sufficiently your scene.

   Regards,

-- 
Jaime Vives Piqueres

http://www.ignorancia.org


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From: SharkD
Subject: Re: LightSys looks_like?
Date: 5 Jun 2010 16:48:36
Message: <4c0ab824$1@news.povray.org>
On 6/5/2010 3:30 AM, Jaime Vives Piqueres wrote:
> El 04/06/10 11:10, SharkD escribió:
>> On 6/4/2010 4:53 AM, SharkD wrote:
>>> Is there a command to make a LightSys light source like a CSG object?
>>> I haven't discovered one yet but am assuming one was created.
>
> No, but you can just attach anything using looks_like. For example, on the
> demo_outdoor scene, you can modify the sun light to this:
>
> light_source{
> SolarPosition
> Light_Color(SunColor,6)
> looks_like{...}
> }

That works, thanks.

-- 
http://isometricland.com


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