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31 Oct 2024 19:29:35 EDT (-0400)
  Question about radiosity (Message 1 to 4 of 4)  
From: clarkking
Subject: Question about radiosity
Date: 26 Jun 2007 21:10:02
Message: <web.4681b84e6bc85a0bb56da8d00@news.povray.org>
I've never used radiosity or hdri lighting so that should give some context
to this current inquiry, and i thank you in advance.

For radiosity to really have an effect on realism in a scene it should be
used when there is more than one object right?  I mean lets say i was
rendering a "portrait" of say some geometric object adding radiosity would
nt have any effect right, except for really long render times.  IN this
case to increase the realism of the object/scene i need to use HDR right.
I know it really depends, but the question stands.


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From: Samuel Benge
Subject: Re: Question about radiosity
Date: 26 Jun 2007 22:29:44
Message: <4681cb98$1@news.povray.org>
clarkking wrote:
> I've never used radiosity or hdri lighting so that should give some context
> to this current inquiry, and i thank you in advance.
> 
> For radiosity to really have an effect on realism in a scene it should be
> used when there is more than one object right?  I mean lets say i was
> rendering a "portrait" of say some geometric object adding radiosity would
> nt have any effect right, except for really long render times.  IN this
> case to increase the realism of the object/scene i need to use HDR right.
> I know it really depends, but the question stands.

Why don't you test it? I always keep a special POV file called
"tester.pov" for these types of things.

To answer your question (I hope): The effects of radiosity can be seen
without the use of HDR or an HDR light probe. Also, you can use HDR
without radiosity. HDR backgrounds can affect a scene either by
reflecting off of reflective surfaces, showing through transparent
surfaces, or through indirect illumination (radiosity).

If you have a white background (not a light probe, just a background
statment set to rgb<1,1,1>), it will illuminate the scene if radiosity
is included in the global_settings block. If you add a light, then you
will see it bounce multiple times depending on the radiosity's
recursion_limit.

In short, you don't need to use HDR in order to use radiosity. Radiosity
alone will increase the realism of your scene.

~Sam


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From: clarkking
Subject: Re: Question about radiosity
Date: 26 Jun 2007 22:35:01
Message: <web.4681cc4ff97fc515b56da8d00@news.povray.org>
Samuel Benge <stb### [at] THIShotmailcom> wrote:
> clarkking wrote:
> > I've never used radiosity or hdri lighting so that should give some context
> > to this current inquiry, and i thank you in advance.
> >
> > For radiosity to really have an effect on realism in a scene it should be
> > used when there is more than one object right?  I mean lets say i was
> > rendering a "portrait" of say some geometric object adding radiosity would
> > nt have any effect right, except for really long render times.  IN this
> > case to increase the realism of the object/scene i need to use HDR right.
> > I know it really depends, but the question stands.
>
> Why don't you test it? I always keep a special POV file called
> "tester.pov" for these types of things.
>
> To answer your question (I hope): The effects of radiosity can be seen
> without the use of HDR or an HDR light probe. Also, you can use HDR
> without radiosity. HDR backgrounds can affect a scene either by
> reflecting off of reflective surfaces, showing through transparent
> surfaces, or through indirect illumination (radiosity).
>
> If you have a white background (not a light probe, just a background
> statment set to rgb<1,1,1>), it will illuminate the scene if radiosity
> is included in the global_settings block. If you add a light, then you
> will see it bounce multiple times depending on the radiosity's
> recursion_limit.
>
> In short, you don't need to use HDR in order to use radiosity. Radiosity
> alone will increase the realism of your scene.
>
> ~Sam



Thanks Sam i am doing that now.  I have my simple scene with radiosity image
saved and now I am doing it with out to see if I can discern any difference.


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From: Alain
Subject: Re: Question about radiosity
Date: 27 Jun 2007 17:54:20
Message: <4682dc8c$1@news.povray.org>
clarkking nous apporta ses lumieres en ce 2007/06/26 22:32:
> Samuel Benge <stb### [at] THIShotmailcom> wrote:
>> clarkking wrote:
>>> I've never used radiosity or hdri lighting so that should give some context
>>> to this current inquiry, and i thank you in advance.
>>>
>>> For radiosity to really have an effect on realism in a scene it should be
>>> used when there is more than one object right?  I mean lets say i was
>>> rendering a "portrait" of say some geometric object adding radiosity would
>>> nt have any effect right, except for really long render times.  IN this
>>> case to increase the realism of the object/scene i need to use HDR right.
>>> I know it really depends, but the question stands.
>> Why don't you test it? I always keep a special POV file called
>> "tester.pov" for these types of things.
>>
>> To answer your question (I hope): The effects of radiosity can be seen
>> without the use of HDR or an HDR light probe. Also, you can use HDR
>> without radiosity. HDR backgrounds can affect a scene either by
>> reflecting off of reflective surfaces, showing through transparent
>> surfaces, or through indirect illumination (radiosity).
>>
>> If you have a white background (not a light probe, just a background
>> statment set to rgb<1,1,1>), it will illuminate the scene if radiosity
>> is included in the global_settings block. If you add a light, then you
>> will see it bounce multiple times depending on the radiosity's
>> recursion_limit.
>>
>> In short, you don't need to use HDR in order to use radiosity. Radiosity
>> alone will increase the realism of your scene.
>>
>> ~Sam
> 
> 
> 
> Thanks Sam i am doing that now.  I have my simple scene with radiosity image
> saved and now I am doing it with out to see if I can discern any difference.
> 
> 
A little trick: Place the radiosity block in an #if(frame_number =2)...#end 
statement and do a 2 frames animation by adding +kff2 on the command line. This 
will give you 2 files named test1 and test2, or whatever name you have used, 
that you can quickly compare.

-- 
Alain
-------------------------------------------------
Light travels faster than sound. That is why some people appear bright until you 
hear them speak.


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