POV-Ray : Newsgroups : povray.binaries.images : HDRI - my tests (79+38k) Server Time
14 Aug 2024 03:23:10 EDT (-0400)
  HDRI - my tests (79+38k) (Message 1 to 5 of 5)  
From: Christoph Hormann
Subject: HDRI - my tests (79+38k)
Date: 2 Jan 2003 05:34:40
Message: <3E1415BE.2C89C391@gmx.de>
Somewhat later than the others but I have made my first tests with image
based lighting using the MLPov hdr image functionality.  Here are two
results.

It seems it works very nicely on surfaces with specular reflections. 
Diffuse surfaces require high rad settings and using normals instead of
real surface geometry looks much more faked than with light sources.

Another difficulty is to find the right hdr map for the intended
lighting.  The probes on

http://www.debevec.org/Probes/

are quite limited in that concern.  Things on

http://www.akuratny.com/hdri.htm

look very promising but lower quality and different mapping (and only
above horizon).  It would be very nice if POV-Ray could also write high
dynamic range images.

I have also made tests for combining HDRI with photons generated using
light sources.  The second attached image shows this.

Christoph

-- 
POV-Ray tutorials, include files, Sim-POV,
HCR-Edit and more: http://www.tu-bs.de/~y0013390/
Last updated 31 Dec. 2002 _____./\/^>_*_<^\/\.______


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Attachments:
Download 'hdri_01.jpg' (79 KB) Download 'hdri_02.jpg' (38 KB)

Preview of image 'hdri_01.jpg'
hdri_01.jpg

Preview of image 'hdri_02.jpg'
hdri_02.jpg


 

From: Mael
Subject: Re: HDRI - my tests (79+38k)
Date: 2 Jan 2003 05:46:24
Message: <3e141880@news.povray.org>
> Somewhat later than the others but I have made my first tests with image
> based lighting using the MLPov hdr image functionality.  Here are two
> results.
> It seems it works very nicely on surfaces with specular reflections.
> Diffuse surfaces require high rad settings and using normals instead of
> real surface geometry looks much more faked than with light sources.

Nice images. I think it's probably possible to improve povray radiosity for
the special case of image lighting (for instance by not using evenly spread
samples, but sending more samples rays towards high intensity area of the
image)

M


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From: Christoph Hormann
Subject: Re: HDRI - my tests (79+38k)
Date: 2 Jan 2003 06:14:34
Message: <3E141F19.4E05D1D0@gmx.de>
Mael wrote:
> 
> Nice images.

Thanks.

> I think it's probably possible to improve povray radiosity for
> the special case of image lighting (for instance by not using evenly spread
> samples, but sending more samples rays towards high intensity area of the
> image)

I already thought of this before but there are a few problems:

- you probably spend quite some time determining which areas are high
intensity at a certain place in the scene.

- you need to weight the samples rays differently to get comparable
results if you have a non uniform distribution.

The first problem could be partly solved by assuming the lighting
situation is the same at all places of the scene.  This should not be a
problem if the sample rays are correctly weighted and the HDR map is far
enough away.  But i'm not sure if it has much advantage then since the
critical areas are always those where the lighting situation is different
because of the scene geometry.

Something else that could be interesting would be 'image based photon
mapping' meaning that you don't send photons from light sources but from
the HDR map.  I'm not sure if that's feasible but it is an interesting
concept i think.

Christoph

-- 
POV-Ray tutorials, include files, Sim-POV,
HCR-Edit and more: http://www.tu-bs.de/~y0013390/
Last updated 31 Dec. 2002 _____./\/^>_*_<^\/\.______


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From: Jaime Vives Piqueres
Subject: Re: HDRI - my tests (79+38k)
Date: 2 Jan 2003 13:00:04
Message: <20030102190004.0f2b070b.jaimevives@ignorancia.org>
On Thu, 02 Jan 2003 11:34:38 +0100
Christoph Hormann <chr### [at] gmxde> wrote:

> 
> Somewhat later than the others but I have made my first tests with
> image based lighting using the MLPov hdr image functionality.  Here
> are two results.

  Impressive, specially the first one: it's amazing. The photons on
the second are very nice too, but the overall lighting is not that
impressive.

-- 
Jaime Vives Piqueres
		
La Persistencia de la Ignorancia
http://www.ignorancia.org


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From: Christoph Hormann
Subject: Re: HDRI - my tests (79+38k)
Date: 2 Jan 2003 15:25:27
Message: <3E14A035.2477C34B@gmx.de>
Jaime Vives Piqueres wrote:
> 
>   Impressive, specially the first one: it's amazing.

Thanks, the map does not really fit the scenery that well but i liked the
colors much more than with most other probes i tried.  

> The photons on
> the second are very nice too, but the overall lighting is not that
> impressive.

Attached is another render of it, this time with a real light source so
there are shadows.  

Christoph

-- 
POV-Ray tutorials, include files, Sim-POV,
HCR-Edit and more: http://www.tu-bs.de/~y0013390/
Last updated 31 Dec. 2002 _____./\/^>_*_<^\/\.______


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Attachments:
Download 'hdri_03.jpg' (39 KB)

Preview of image 'hdri_03.jpg'
hdri_03.jpg


 

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