Hi,
	I got that error at frame 12 out of 100, saying:
Rendering error.
Too few sampling intervals.

I guess this is related to my media sample? here is my media code:
#declare theMedia = media {
	scattering { 1 rgb 1 extinction 0.01 }
	samples 1, 10
}

Can somebody tell me what is not right, why and how to avoid such mistake in the
future?

Thanks,
	Simon

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I just figured there is another setting which is called intervals and is set to
10 by default, since the error says Too few sampling intervals, I tried it to 20
and it worked...

	But I'm still wondering how to predict this kind of error, it happened on frame
12 of my animation... I looked at 1, 2 maybe 3 and went away from home for a
couple of hours...

Why were there too few sampling intervals?

Thanks,
	Simon

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Simon Lemieux wrote in message <39416CDF.7DEF3223@yahoo.com>...
>I just figured there is another setting which is called intervals and is
set to
>10 by default, since the error says Too few sampling intervals, I tried it
to 20
>and it worked...
>
> But I'm still wondering how to predict this kind of error, it happened on
frame
>12 of my animation... I looked at 1, 2 maybe 3 and went away from home for
a
>couple of hours...


Each time a ray is traced through a scattering media (or, I think, any other
media), the ray is divided up into intervals whenever it enters or leaves a
spotlight cone.  Internally, the memory needed to keep track of these
intervals is allocated before doing anything else.  This means that POV-Ray
needs to know how many intervals there are before starting to trace the ray
through the media.  The error occurs when there are more intervals than can
be stored in the memory allocated for them.

There are two ways of avoiding this error:
1) Multiply the number of spotlights/cylinder lights by 2 and use this as
your "intervals" number.  This will probably be more intervals than you will
need, but it is possible that all of them will be needed.

2) Get MegaPov and forget about intervals entirely.  Nathan Kopp fixed this
problem by having POV-Ray figure out how many intervals are needed for the
ray before allocating the memory.

Mark

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On Fri, 09 Jun 2000 18:08:03 -0400, Simon Lemieux
<lem### [at] yahoocom> wrote:

>Hi,
>	I got that error at frame 12 out of 100, saying:
>Rendering error.
>Too few sampling intervals.

>Can somebody tell me what is not right, why and how to avoid such mistake in the
>future?

This is related to the way POV samples te media density. It takes a
ray and divides the part of it which is in a media container into
several intervals, then takes some samples in each interval. It gives
more precedence to spotlights than pointlights so if you have many
spotlight cones intersecting the ray in question, POV will not be able
to give each its own interval and will exit with an error. At least
that's what I think is happening. Whatever the exact cause, there are
two ways to prevent it or overcome it. Increase the intervals or get
MegaPOV which has no such problems.


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

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