POV-Ray : Newsgroups : povray.binaries.images : tricky rad Server Time
15 Aug 2024 00:13:27 EDT (-0400)
  tricky rad (Message 1 to 5 of 5)  
From: Jaime Vives Piqueres
Subject: tricky rad
Date: 28 Aug 2002 03:38:17
Message: <3d6c7de8@news.povray.org>
What do you think about the radiosity on this scene? Seems correct for a 
little room with indirect sunlight? 

-- 
Jaime Vives Piqueres

La Persistencia de la Ignorancia
http://www.ignorancia.org


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Attachments:
Download 'faked_rad.jpg' (14 KB)

Preview of image 'faked_rad.jpg'
faked_rad.jpg


 

From: ABX
Subject: Re: tricky rad
Date: 28 Aug 2002 03:46:24
Message: <dnvomucttsevrg9t2p0bqb9ppmfab2t81q@4ax.com>
On Wed, 28 Aug 2002 09:46:25 +0200, Jaime Vives Piqueres
<jai### [at] ignoranciaorg> wrote:
> What do you think about the radiosity on this scene? Seems correct for a 
> little room with indirect sunlight? 

Somehow I feel it incorrect. Transition from dark to light on the same areas
seems unnatural but it can be illusion and/or result of blur. Before showing
what trick you have used (I assume it gives very fast rendering) please send
real radiosity version for comparision.

ABX


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From: Dave Blandston
Subject: Re: tricky rad
Date: 28 Aug 2002 06:26:58
Message: <3d6ca572@news.povray.org>
It doesn't look right to me for this reason: there is a very strong tint of
color on the walls and floor near the red, green, and blue objects
(especially the green one), but for such a strong tint, it fades too quickly
farther away from the objects. Maybe the colors are canceling each other
out?

Regards,
-Dave Blandston

"Jaime Vives Piqueres" <jai### [at] ignoranciaorg> wrote in message
news:3d6c7de8@news.povray.org...
> What do you think about the radiosity on this scene? Seems correct for a
> little room with indirect sunlight?
>
> --
> Jaime Vives Piqueres
>
> La Persistencia de la Ignorancia
> http://www.ignorancia.org


Post a reply to this message

From: Jaime Vives Piqueres
Subject: Re: tricky rad
Date: 28 Aug 2002 09:28:39
Message: <3d6cd005@news.povray.org>
ABX wrote:
> Somehow I feel it incorrect. Transition from dark to light on the same
> areas seems unnatural but it can be illusion and/or result of blur. 

  Yes, I feel also the same.  It's a side-effect of the trick used, but I 
will try to minimize it. Blur doesn't has nothing to do with it, and 
perhaps helps hidding the fact.

> Before showing what trick you have used (I assume it gives very fast 
> rendering) please send real radiosity version for comparision.

  That's the problem, and my motivation to do the trick: I can't get that 
kind of lighting only with pure rad and one light_source outside. Surely 
it's possible, but I've not the patience needed to find and test the high 
quality settings... I'm very lazy, do you remember? :)

  The original image on the first post uses an extra area_light placed 
carefully on the window hole, to simulate the external rad coming in, with 
"Radiosity_Normal". The image called "faked_rad_normal.jpg" shows the same 
setup with only the outside light (almost no visible rad effect). The image 
"faked_rad_no-aa.jpg" uses also the same tricky extra light, but without 
the area_light statement (to show better how it is placed). 

 I've tried this trick on my "alchlab" image done with Megapov, but seems 
that it works better with 3.5. I will try to add an spotlight statement 
automated to follow the sun position, to give it a more directional look.

-- 
Jaime Vives Piqueres

La Persistencia de la Ignorancia
http://www.ignorancia.org


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Attachments:
Download 'faked_rad_no-aa.jpg' (9 KB) Download 'faked_rad_normal.jpg' (3 KB)

Preview of image 'faked_rad_no-aa.jpg'
faked_rad_no-aa.jpg

Preview of image 'faked_rad_normal.jpg'
faked_rad_normal.jpg


 

From: Jaime Vives Piqueres
Subject: Re: tricky rad
Date: 28 Aug 2002 09:28:50
Message: <3d6cd011@news.povray.org>
Dave Blandston wrote:

> It doesn't look right to me for this reason: there is a very strong tint
> of color on the walls and floor near the red, green, and blue objects
> (especially the green one), but for such a strong tint, it fades too
> quickly farther away from the objects. Maybe the colors are canceling each
> other out?

  Your right: seems the tint is a bit excessive. But not too much, I think: 
I've been looking at real situations and some surfaces with intense colors 
seem to behave this way, in an very directinal way. I think it's a side 
effect of having actually two light sources: it increases the tint effect 
of radiosity.

-- 
Jaime Vives Piqueres

La Persistencia de la Ignorancia
http://www.ignorancia.org


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