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From: Gilles Tran
Subject: More HDRI tests (136 kbu)
Date: 25 Dec 2002 14:33:11
Message: <3e0a07f7@news.povray.org>
Last ones before it gets boring... In fact I guess that similar results
could be obtained with regular maps, lol.
Xfrog rose, Rhino glasses. I had to touch up some residual focal blur
graininess.

G.

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From: Slime
Subject: Re: More HDRI tests (136 kbu)
Date: 25 Dec 2002 19:50:29
Message: <3e0a5255@news.povray.org>
What exactly is HDRI? It looks to me like some sort of special "radiosity"
that only takes the sky_sphere into account and treats it as light sources.
But I can't figure out exactly what is happening.

It's certainly not getting boring, though... these images are extremely
impressive. Photorealistic. I love the red one. Hmm... where'd you get the
rose model?

 - Slime
[ http://www.slimeland.com/ ]


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From: Gilles Tran
Subject: Re: More HDRI tests (136 kbu)
Date: 25 Dec 2002 20:53:17
Message: <3e0a610d@news.povray.org>

3e0a5255@news.povray.org...
> What exactly is HDRI? It looks to me like some sort of special "radiosity"
> that only takes the sky_sphere into account and treats it as light
sources.
> But I can't figure out exactly what is happening.

I guess it's explained here.
http://athens.ict.usc.edu/Research/HDR/
I tend to think of HDR maps as photographs with the ability to blind those
who see them...

> It's certainly not getting boring, though... these images are extremely
> impressive. Photorealistic. I love the red one.
Thanks. These are merely tests though, they just turned out better than they
were meant to. If I get the time, I'll develop them later (better textures
etc.).

> Hmm... where'd you get the rose model?
It's an Xfrog model from their "Flowers 1" collection.

G.


--
**********************
http://www.oyonale.com
**********************
- Graphic experiments
- POV-Ray and Poser computer images
- Posters


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From: ZSpider
Subject: Re: More HDRI tests (136 kbu)
Date: 26 Dec 2002 09:29:13
Message: <3e0b1239$1@news.povray.org>
Gilles Tran wrote:
> Last ones before it gets boring... In fact I guess that similar results
> could be obtained with regular maps, lol.
> Xfrog rose, Rhino glasses. I had to touch up some residual focal blur
> graininess.

*********
Beautiful images, Gilles.  I looked at some of the HDRI links you
provided for Slime, and I understood the explanation for a while,
but then it got sorta fuzzy.  The HDR shop is a post-processor that's
applied after rendering, isn't it?  Is that what you used?

Thanks, miker


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From: Gilles Tran
Subject: Re: More HDRI tests (136 kbu)
Date: 26 Dec 2002 11:07:50
Message: <3e0b2956$1@news.povray.org>

3e0b1239$1@news.povray.org...
>Beautiful images, Gilles.
Thanks !

> The HDR shop is a post-processor that's
> applied after rendering, isn't it?  Is that what you used?

I'd rather let the experts explain what this is all about because it's quite
fuzzy for me too !
Basically the trick is to get a HDR file and use it on a big sphere in a
radiosity scene. This I figured out.
What HDR shop does is 1) let you view and edit HDR files and 2) create HDR
files out of sequences of normal images (particularly ones from digital
cameras).
Actually this part is *** very *** confusing to me right now. Anyone knows
if it possible to take a single regular image and turn it into a HDR version
? I've tried it and get a HDR file but I'm not sure it really works (or make
sense at all ?)...

G.


--
**********************
http://www.oyonale.com
**********************
- Graphic experiments
- POV-Ray and Poser computer images
- Posters


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From: Martial
Subject: Re: More HDRI tests (136 kbu)
Date: 26 Dec 2002 11:21:29
Message: <3e0b2c89$1@news.povray.org>
If you no see on  p.g or p.u.p
There are a litle bug with material_map 
The files corrected (source and exe) : 
(same name of version mlpov081 122302) 
 http://martial.rameaux.free.fr/mael/mlpov81eng.html 


Thanks Mael !

--
Martial


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From: Ive
Subject: Re: More HDRI tests (136 kbu)
Date: 26 Dec 2002 14:29:59
Message: <3e0b58b7$1@news.povray.org>
> I'd rather let the experts explain what this is all about because it's quite
> fuzzy for me too !
> Basically the trick is to get a HDR file and use it on a big sphere in a
> radiosity scene. This I figured out.
> What HDR shop does is 1) let you view and edit HDR files and 2) create HDR
> files out of sequences of normal images (particularly ones from digital
> cameras).
> Actually this part is *** very *** confusing to me right now. Anyone knows
> if it possible to take a single regular image and turn it into a HDR version
> ? I've tried it and get a HDR file but I'm not sure it really works (or make
> sense at all ?)...
>

First HDR has nothing to do with the kind of mapping you use. If you look at
Paul Debevec' page you'll find also box-mapped HDR images or simple planar
ones. High Dynamic Range Images means that the full color indensity (or better
the lumens) is also stored into the image file. This is a much better representation
of "reality" as Low Dynamic Range as represented by using the (poor) RGB
color space (used within jpg or png files). POV does internal work with high
dynamic range and I guess most of you have already used a light source that is
"brighter" than rgb <1,1,1>. I usually do so and this is the way Jaime's lighting
system does work. This is also "HDR".
Imaging a white sheet of paper, white clauds on a sunny day, the sun itself or
a exploding super nova. In rgb color space, all of them are represented as
simple rgb <1,1,1>. And as POV does already calculate with HDR values
it seems really logic and useful to me not to be restricted when it comes to
input AND output if image formats. This would give you simply the similar
possibilities that are normal to any photographer.
Oh, and one more thing: HDR means simply that the full range of gamut and
lumens is coverd by the image format. The files from Paul Debevec' page are
in the Radiance-format as developed by Greg Ward, who did also design the
LogLUV format  (also HDR). There are others around as e.g. TIFF-Pixar-Log
as used by (you guessed it) Pixar.

-Ive


P.S. sorry Gilles it did happen again, wrong button in Outlook.


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From: Slime
Subject: Re: More HDRI tests (136 kbu)
Date: 26 Dec 2002 15:20:13
Message: <3e0b647d@news.povray.org>
> Actually this part is *** very *** confusing to me right now. Anyone knows
> if it possible to take a single regular image and turn it into a HDR
version
> ? I've tried it and get a HDR file but I'm not sure it really works (or
make
> sense at all ?)...


From what I read in the links you gave me, it seems that HDR is an image
format that lets you store non-clipped color values. (normal images cover
RGB values 0-255 (really 0.0 - 1.0), whereas HDR lets you cover 0.0 to
infinity... or maybe even negative infinity to infinity, I'm not sure.)

So you couldn't get an HDR image from a single photograph, since all that
photograph contains is values from 0 to 1, and you need more photographs
with different exposure times to get more information.

That's about all I can figure out.

 - Slime
[ http://www.slimeland.com/ ]


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From: George Pantazopoulos
Subject: Re: More HDRI tests (136 kbu)
Date: 26 Dec 2002 16:55:13
Message: <3e0b7ac1@news.povray.org>
Thats correct Slime :) I've made a few square ones myself using just my
webcam and adjusting the exposure settings.. and using HDRShop.. its really
cool

George Pantzopoulos
>
>
> From what I read in the links you gave me, it seems that HDR is an image
> format that lets you store non-clipped color values. (normal images cover
> RGB values 0-255 (really 0.0 - 1.0), whereas HDR lets you cover 0.0 to
> infinity... or maybe even negative infinity to infinity, I'm not sure.)
>
> So you couldn't get an HDR image from a single photograph, since all that
> photograph contains is values from 0 to 1, and you need more photographs
> with different exposure times to get more information.
>
> That's about all I can figure out.
>
>  - Slime
> [ http://www.slimeland.com/ ]
>
>


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From: Apache
Subject: Re: More HDRI tests (136 kbu)
Date: 26 Dec 2002 17:41:44
Message: <3e0b85a8@news.povray.org>
Well.... why don't you render us some nice pics then?


:-)

Apache


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