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4 Nov 2024 17:34:37 EST (-0500)
  radiosity using diffuse, or pigment for calc.? (Message 1 to 3 of 3)  
From: Bob H 
Subject: radiosity using diffuse, or pigment for calc.?
Date: 10 Oct 2001 16:44:49
Message: <3bc4b341$1@news.povray.org>
Only an observation... I noticed how pigment color seems to be the dominant
brightness factor for radiosity, and that diffuse might have a upper limit
or clipping involved which prevents very high values of diffuse from
contributing to the illumination.
I had understood that ambient was replaced by diffuse but I didn't think
there was a limitation of its influence, and yet color doesn't have a limit
from what I can tell.
Well, let me rephrase that.  What I'm saying is that if one object has high
diffuse and another doesn't (non-zero though) that you can apply diffuse
1000 to the first object and still get no significant brightness change in
the neighboring object.  However, I think if color is raised to whatever
high value it does change.

Anyone else care to chime in about that?

Bob H.
--
http://webpages.charter.net/omniverse/omniverse.htm


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From: Trevor Quayle
Subject: Re: radiosity using diffuse, or pigment for calc.?
Date: 10 Oct 2001 16:51:50
Message: <3bc4b4e6@news.povray.org>
As I understand the explaination in the docs:
The diffuse value affects the how the object picks up light and appears
itself.  It isn't used to transmit light to other objects, the color (and
therefore, ambient) is used for this.

-tgq


"Bob H." <omn### [at] msncom> wrote in message
news:3bc4b341$1@news.povray.org...
> Only an observation... I noticed how pigment color seems to be the
dominant
> brightness factor for radiosity, and that diffuse might have a upper limit
> or clipping involved which prevents very high values of diffuse from
> contributing to the illumination.
> I had understood that ambient was replaced by diffuse but I didn't think
> there was a limitation of its influence, and yet color doesn't have a
limit
> from what I can tell.
> Well, let me rephrase that.  What I'm saying is that if one object has
high
> diffuse and another doesn't (non-zero though) that you can apply diffuse
> 1000 to the first object and still get no significant brightness change in
> the neighboring object.  However, I think if color is raised to whatever
> high value it does change.
>
> Anyone else care to chime in about that?
>
> Bob H.
> --
> http://webpages.charter.net/omniverse/omniverse.htm
>
>


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From: Bob H 
Subject: Re: radiosity using diffuse, or pigment for calc.?
Date: 10 Oct 2001 17:13:58
Message: <3bc4ba16@news.povray.org>
"Trevor Quayle" <Tin### [at] hotmailcom> wrote in message
news:3bc4b4e6@news.povray.org...
> As I understand the explaination in the docs:
> The diffuse value affects the how the object picks up light and appears
> itself.  It isn't used to transmit light to other objects, the color (and
> therefore, ambient) is used for this.

Hmm, food for thought.

Unfortunately I was sitting here thinking about render tests I had been
doing and kind of spoke out loud here as I wondered about it.  I mistakenly
said how ambient wasn't used anymore when what I was thinking about was the
MegaPOV (okay, okay, I know the phrase) way in which ambient 0 was the norm
for when radiosity was to be done.  Obviously now in 3.5 it's okay to use
ambient light from what I've gathered about it.  Still, what puzzled me is
how diffuse can be so steadfast and unchanging when in an environment that
ought to be affecting it.  I think this is my misunderstanding, since
diffuse is often used as a color buffer, as opposed to a color enhancer as
with ambient.  However, BTW, I tried high ambience too and really only color
(pigment) was the dominant force.

Not sure I'm describing anything correctly here but maybe its still
readable.

Bob H.


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