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From: daishi
Subject: photon mapping problem
Date: 4 Apr 2000 21:08:44
Message: <38EA9065.19BFC771@x-press.net>
I can't seem to get photon mapping to work properly (here is the address
for what the image looks like rendered in rhino,
http://daishi.50megs.com/caustic_test.html )

whenever it builds the photon map it either

a) doesn't build it (if I specifiy the number of photons, or use
autostep 0 )
or
b) never stops building the map, it gets to about 78500 photons hit the
object and then it just continues to shoot photons, but the number of
photons that actully strike the object never goes up and it just keeps
shooting photons at it until it runs out of memory (it tried to
allocated 327mb for the photon map)

the only thing I can think of is maybe the object is to complicated to
work with pov-ray's photon mapping (I only have 128mb of ram) or photon
mapping doesn't work properly with triange mesh's (which is what rhino
exports its files as)

the pov-ray file is attached below
any help is mucho appreciated

note: I didn't attach the mesh files for the object since its 18mb


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Attachments:
Download 'caustics_test.pov.txt' (3 KB)

From: Ken
Subject: Re: photon mapping problem
Date: 4 Apr 2000 21:57:45
Message: <38EA9D68.233220AB@pacbell.net>
daishi wrote:

> the only thing I can think of is maybe the object is to complicated to
> work with pov-ray's photon mapping (I only have 128mb of ram) or photon
> mapping doesn't work properly with triange mesh's (which is what rhino
> exports its files as)

Try manually bounding the mesh object.

-- 
Ken Tyler -  1300+ Povray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/


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From: daishi
Subject: Re: photon mapping problem
Date: 4 Apr 2000 22:42:13
Message: <38EAA650.2E40C03F@x-press.net>
did that, and when I render it it says "removed unnessecary bounding object"
or something like that

Ken wrote:

> daishi wrote:
>
> > the only thing I can think of is maybe the object is to complicated to
> > work with pov-ray's photon mapping (I only have 128mb of ram) or photon
> > mapping doesn't work properly with triange mesh's (which is what rhino
> > exports its files as)
>
> Try manually bounding the mesh object.
>
> --
> Ken Tyler -  1300+ Povray, Graphics, 3D Rendering, and Raytracing Links:
> http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/


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From: Ken
Subject: Re: photon mapping problem
Date: 4 Apr 2000 23:38:42
Message: <38EAB50A.FE3772E2@pacbell.net>
daishi wrote:
> 
> did that, and when I render it it says "removed unnessecary bounding object"
> or something like that

In the povray.ini file add the following:  bounding=off

This will prevent the removal of your manual bounding.

-- 
Ken Tyler -  1300+ Povray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/


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From: daishi
Subject: Re: photon mapping problem
Date: 4 Apr 2000 23:52:10
Message: <38EAB6B5.682215F2@x-press.net>
tried that, still gives me the same error
I also tried rendering with the -MB option, same thing

Ken wrote:

> daishi wrote:
> >
> > did that, and when I render it it says "removed unnessecary bounding object"
> > or something like that
>
> In the povray.ini file add the following:  bounding=off
>
> This will prevent the removal of your manual bounding.
>
> --
> Ken Tyler -  1300+ Povray, Graphics, 3D Rendering, and Raytracing Links:
> http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/


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From: daishi
Subject: Re: photon mapping problem
Date: 4 Apr 2000 23:56:34
Message: <38EAB7BF.20FE5B4C@x-press.net>
I got it to stop removing my manual bounding, its -UR is the command option

but its still shooting photons at the object for forever, maybe I'll just let it run
out of memeory and see if anything different happens this time

daishi wrote:

> tried that, still gives me the same error
> I also tried rendering with the -MB option, same thing
>
> Ken wrote:
>
> > daishi wrote:
> > >
> > > did that, and when I render it it says "removed unnessecary bounding object"
> > > or something like that
> >
> > In the povray.ini file add the following:  bounding=off
> >
> > This will prevent the removal of your manual bounding.
> >
> > --
> > Ken Tyler -  1300+ Povray, Graphics, 3D Rendering, and Raytracing Links:
> > http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/


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From: Warp
Subject: Re: photon mapping problem
Date: 5 Apr 2000 08:00:41
Message: <38eb2ae8@news.povray.org>
daishi <das### [at] x-pressnet> wrote:
: This is a multi-part message in MIME format.

  Please don't send mime-encoded messages nor binary attachments to a
non-binaries group.
  Thanks.

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/


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From: Nathan Kopp
Subject: Re: photon mapping problem
Date: 5 Apr 2000 09:19:11
Message: <38eb3d4f$1@news.povray.org>
daishi <das### [at] x-pressnet> wrote...
> b) never stops building the map, it gets to about 78500 photons hit the
> object and then it just continues to shoot photons, but the number of
> photons that actully strike the object never goes up and it just keeps
> shooting photons at it until it runs out of memory (it tried to
> allocated 327mb for the photon map)

If you're using spacing (as opposed to count), use a larger spacing.  Also,
try manually bounding the object (as previously suggested, and make sure you
tell POV not to remove your manual bounds).  Finally, use an autostop of 0.5
or so.  Autostop of zero doesn't work because the object has a hole in the
middle.  If the photons quit striking the object, POV shouldn't try to
allocate any more memory.  WinMegaPov displays a total number of photons as
it builds the map, and if that number stops going up (meaning that the
remaining photons are missing their target), you shouldn't get any more
memory allocated for the photon map.

-Nathan


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From: daishi
Subject: Re: photon mapping problem
Date: 5 Apr 2000 12:41:28
Message: <38EB6AFC.D09DE447@x-press.net>
I tried setting the spacing to 1, and the autostop to .5 (oh btw if I use count
it doesn't generate the photon map either, I've even tried 2 million photons and
it still wouldn't generate the map)
about 38k photons hit the object, and it just keeps shooting them forever
(meaning the amount of photons that actully strike the object never goes up)

it seems if I specifiy an autostop greater then 0 it will continue to shoot
photons at the object for an infinate amount of time, if I specifiy autostop 0
though it doesn't even build the photon maps....

ugh, I don't have any infinate objects in my scene, just 2 polygon mesh's the
object and the floor, and just to be sure the floor wasn't the problem I put
ignore_photons in the object declaration

Nathan Kopp wrote:

> daishi <das### [at] x-pressnet> wrote...
> > b) never stops building the map, it gets to about 78500 photons hit the
> > object and then it just continues to shoot photons, but the number of
> > photons that actully strike the object never goes up and it just keeps
> > shooting photons at it until it runs out of memory (it tried to
> > allocated 327mb for the photon map)
>
> If you're using spacing (as opposed to count), use a larger spacing.  Also,
> try manually bounding the object (as previously suggested, and make sure you
> tell POV not to remove your manual bounds).  Finally, use an autostop of 0.5
> or so.  Autostop of zero doesn't work because the object has a hole in the
> middle.  If the photons quit striking the object, POV shouldn't try to
> allocate any more memory.  WinMegaPov displays a total number of photons as
> it builds the map, and if that number stops going up (meaning that the
> remaining photons are missing their target), you shouldn't get any more
> memory allocated for the photon map.
>
> -Nathan


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From: Warp
Subject: Re: photon mapping problem
Date: 6 Apr 2000 03:38:58
Message: <38ec3f10@news.povray.org>
daishi <das### [at] x-pressnet> wrote:
: about 38k photons hit the object, and it just keeps shooting them forever

  Have you bounded the object?

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/


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