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25 Dec 2024 20:50:59 EST (-0500)
  .df3 with many intervals: out of memory error (Message 1 to 3 of 3)  
From: Frank
Subject: .df3 with many intervals: out of memory error
Date: 23 Feb 2008 00:20:01
Message: <web.47bfac90ac28e73826eb43d10@news.povray.org>
I'm trying to render a medical data set in a movie. I am using the MRI code at
http://ozviz.wasp.uwa.edu.au/~pbourke/modelling_rendering/df3/ as a starting
point. However, my .df3 file is slightly larger (250 by 250 by 350
1-byte-values). I'm rendering on a 16 GB quad-core workstation with the beta
3.7.0.beta.25, because I need to make use of the multicore architecture.

The beta gives me an "out-of-memory", while 3.6 works without problems.
Strangely enough, in the strace, I cannot find a failing mmap. The reason for
the failure seems to be a large intervals count: lowering it to 30 from 100
solves my problem. Here's the code cooked down just to show the problem:

camera {
   location 0
   look_at z }
#declare theinterior = interior {
   media {
      intervals 100
      density {
                density_file df3 "maus.df3" } } }
box {
   <0,0,0>, <1,1,1>
   interior { theinterior }
   hollow }

Fatal error in renderer: Out of memory.
Render failed


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From: Alain
Subject: Re: .df3 with many intervals: out of memory error
Date: 23 Feb 2008 18:27:37
Message: <47c0abe9$1@news.povray.org>
Frank nous apporta ses lumieres en ce 2008/02/23 00:18:
> I'm trying to render a medical data set in a movie. I am using the MRI code at
> http://ozviz.wasp.uwa.edu.au/~pbourke/modelling_rendering/df3/ as a starting
> point. However, my .df3 file is slightly larger (250 by 250 by 350
> 1-byte-values). I'm rendering on a 16 GB quad-core workstation with the beta
> 3.7.0.beta.25, because I need to make use of the multicore architecture.
> 
> The beta gives me an "out-of-memory", while 3.6 works without problems.
> Strangely enough, in the strace, I cannot find a failing mmap. The reason for
> the failure seems to be a large intervals count: lowering it to 30 from 100
> solves my problem. Here's the code cooked down just to show the problem:
> 
> camera {
>    location 0
>    look_at z }
> #declare theinterior = interior {
>    media {
>       intervals 100
>       density {
>                 density_file df3 "maus.df3" } } }
> box {
>    <0,0,0>, <1,1,1>
>    interior { theinterior }
>    hollow }
> 
> Fatal error in renderer: Out of memory.
> Render failed
> 
> 
> 
> 
As the default sampling method is the adaptive one, you should leave intervals 
at it's default value of 1 (not 10 as the documentation imply).
Instread, whenever you need more sampling, increase the samples value.
You will also see that your render time will get beter.

samples 1000 is way faster than samples 10 intervals 100

The documentation actualy refer to the former default of sampling method 1. The 
defaults are now:
method 3
samples 3
intervals 1

You can use samples 3,4 but the second value is always ignored by method 3.

-- 
Alain
-------------------------------------------------
Agnostic: Did someone shit?


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From: Frank
Subject: Re: .df3 with many intervals: out of memory error
Date: 26 Feb 2008 08:05:01
Message: <web.47c40de9a35ead537597f0180@news.povray.org>
Alain <ele### [at] netscapenet> wrote:
> As the default sampling method is the adaptive one, you should leave intervals
> at it's default value of 1 (not 10 as the documentation imply).
Yupp, that's it. Thank you.

Frank


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