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From: Apache
Subject: saving radiosity data
Date: 29 Nov 2001 01:53:05
Message: <3c05db51@news.povray.org>
According to POV-Ray Help it is not a good idea to save and load radiosity
data with 'save_file' and 'load_file' if scene objects are moving. I'm
wondering if this includes the camera. Can I reuse the radiosity data after
only moving the camera position?

If so, I can safe lotsa time with animations only involving the camera
position.


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From: Christoph Hormann
Subject: Re: saving radiosity data
Date: 29 Nov 2001 02:11:20
Message: <3C05DF97.CE777E66@gmx.de>
Apache wrote:
> 
> According to POV-Ray Help it is not a good idea to save and load radiosity
> data with 'save_file' and 'load_file' if scene objects are moving. I'm
> wondering if this includes the camera. Can I reuse the radiosity data after
> only moving the camera position?
> 
> If so, I can safe lotsa time with animations only involving the camera
> position.

No, that's not a good idea. In Povray radiosity data is only calculated
for the area visible so changing the camera view will lead to bad results
too.

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/


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From: Apache
Subject: Re: saving radiosity data
Date: 29 Nov 2001 02:20:41
Message: <3c05e1c9$1@news.povray.org>
So 'save_file' safes time only in case of resuming aborted renders without
any scene changes?


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From: Christoph Hormann
Subject: Re: saving radiosity data
Date: 29 Nov 2001 03:07:41
Message: <3C05ECCC.591F00DC@gmx.de>
Apache wrote:
> 
> So 'save_file' safes time only in case of resuming aborted renders without
> any scene changes?

In fact it's 'load_file' what saves time of course, but yes, that's
correct.  Of course it also helps when rerendering with changed render
parameters like antialiasing etc.

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/


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From: Peter Popov
Subject: Re: saving radiosity data
Date: 29 Nov 2001 08:59:06
Message: <e9fc0uk9qv4e2agcp2ee8dff51iq8r8a0g@4ax.com>
On Thu, 29 Nov 2001 07:43:40 +0100, "Apache"
<apa### [at] yahoocom> wrote:

>According to POV-Ray Help it is not a good idea to save and load radiosity
>data with 'save_file' and 'load_file' if scene objects are moving. I'm
>wondering if this includes the camera. Can I reuse the radiosity data after
>only moving the camera position?
>
>If so, I can safe lotsa time with animations only involving the camera
>position.

The algorithm POV-Ray uses for global illumination does not calculate
diffuse interreflections for the whole scenes, as do true radiosity
renderers such as Radiance. It only calculates and stores what it
needs considering the camera field of vision. The result? Well, what
you're asking for is generally impossible.

There may be a workaround in some cases, though.

Imagine a room lit by a light bulb. The bulb is places so that it
illuminates most of the room directly, and radiosity will take care of
the rest. In other words, any point in the room is a ray "hop" or two
away from the light source. Therefore, you may place a spherical
camera coinciding with the light source and save the radiosity data,
then reuse it in a "fly around" or "turn around" type of animation. If
you use very high quality settings to gather radiosity data, it might
just work.

I haven't tested it but I intend to when I finish model ling my
current scene.


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] vipbg
TAG      e-mail : pet### [at] tagpovrayorg


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From: Thorsten Froehlich
Subject: Re: saving radiosity data
Date: 29 Nov 2001 14:59:00
Message: <3c069384$1@news.povray.org>
In article <3C05ECCC.591F00DC@gmx.de> , Christoph Hormann 
<chr### [at] gmxde>  wrote:

> In fact it's 'load_file' what saves time of course, but yes, that's
> correct.  Of course it also helps when rerendering with changed render
> parameters like antialiasing etc.

I thought the radiosity data file is kept when interrupting a render so a
continue trace is always possible, which I am fairly sure worked in 3.1???

    Thorsten


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From: Christoph Hormann
Subject: Re: saving radiosity data
Date: 29 Nov 2001 15:45:45
Message: <3C069E7A.BED08B66@gmx.de>
Thorsten Froehlich wrote:
> 
> I thought the radiosity data file is kept when interrupting a render so a
> continue trace is always possible, which I am fairly sure worked in 3.1???
> 

Not in the windows version, with Linux it was possible in 3.1, don't know
about 3.5 of course.  If it's also standard in the Mac version, it should
maybe be changed in WinPov.

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/


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From: Warp
Subject: Re: saving radiosity data
Date: 29 Nov 2001 16:09:18
Message: <3c06a3fe@news.povray.org>
Christoph Hormann <chr### [at] gmxde> wrote:
: Not in the windows version, with Linux it was possible in 3.1, don't know
: about 3.5 of course.  If it's also standard in the Mac version, it should
: maybe be changed in WinPov.

  I agree with that. It worked that way in the DOS-version, it works that
way in unix and apparently in MacOS. Why it doesn't work that way in Windows
is a mystery to me.

-- 
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}//                     - Warp -


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From: Warp
Subject: Re: saving radiosity data
Date: 29 Nov 2001 16:11:47
Message: <3c06a493@news.povray.org>
If you calculate radiosity with a higher recursion level (eg. 3 or 4) then
povray calculates illumination of many hidden-to-the-camera surfaces as well.
  It would be interesting to try doing this and then moving the camera to see
what happens.

-- 
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}//                     - Warp -


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From: Thorsten Froehlich
Subject: Re: saving radiosity data
Date: 3 Dec 2001 17:03:09
Message: <3c0bf69d$1@news.povray.org>
In article <3c06a3fe@news.povray.org> , Warp <war### [at] tagpovrayorg>  wrote:

>  Why it doesn't work that way in Windows is a mystery to me.

It should work.  If it doesn't, you know what to do.

    Thorsten

____________________________________________________
Thorsten Froehlich
e-mail: mac### [at] povrayorg

I am a member of the POV-Ray Team.
Visit POV-Ray on the web: http://mac.povray.org


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