POV-Ray : Newsgroups : povray.general : Parse Error? Server Time
2 Aug 2024 14:16:08 EDT (-0400)
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From: Tim Nikias
Subject: Parse Error?
Date: 10 Oct 2004 17:41:53
Message: <4169aca1$1@news.povray.org>
"Parse Error: Singular matrix in MInvers."

What does that tell me? It is solved by placing the camera slightly
somewhere else. All that's in the scene are some meshes, CSG and
lightsources. Of course used with several macros, and the mesh-files are
pretty large, hence I won't post it. First time it happened to me any way,
so I guess it's some rare tedious to track problem. Does it have anything to
do with the meshes perhaps?

Regards,
Tim

-- 
"Tim Nikias v2.0"
Homepage: <http://www.nolights.de>


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From: JWV
Subject: Re: Parse Error?
Date: 10 Oct 2004 18:48:12
Message: <4169bc2c$1@news.povray.org>
just a wild guess:

MInvers appears to create the inverse matrix A^-1 of A(so that (A^-1)*A=I).
Singular is just another way of saying that a matrix can not be inverted.

Have no idea what POV-ray needs an inverse matrix for, but I think it has
something to do with the mesh (?).

Greetings,

JWV

"Tim Nikias" <JUSTTHELOWERCASE:timISNOTnikias(at)gmx.netWARE> wrote in
message news:4169aca1$1@news.povray.org...
> "Parse Error: Singular matrix in MInvers."
>
> What does that tell me? It is solved by placing the camera slightly
> somewhere else. All that's in the scene are some meshes, CSG and
> lightsources. Of course used with several macros, and the mesh-files are
> pretty large, hence I won't post it. First time it happened to me any way,
> so I guess it's some rare tedious to track problem. Does it have anything
to
> do with the meshes perhaps?
>
> Regards,
> Tim
>
> -- 
> "Tim Nikias v2.0"
> Homepage: <http://www.nolights.de>
>
>


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From: Tim Nikias
Subject: Re: Parse Error?
Date: 10 Oct 2004 18:54:07
Message: <4169bd8f$1@news.povray.org>
> just a wild guess:
>
> MInvers appears to create the inverse matrix A^-1 of A(so that
(A^-1)*A=I).
> Singular is just another way of saying that a matrix can not be inverted.
>
> Have no idea what POV-ray needs an inverse matrix for, but I think it has
> something to do with the mesh (?).

Heh, you just rephrased my question on a more technical level. :-) I was
rather hoping to get an answer along the lines of where the source of the
problem might be, if it really is the mesh, or something with the camera.
OTOH, if that message is just generally stating that an inverse of a matrix
cannot be calculated, then I guess it could be anything and is probably not
a bug that is possible to fix, as it would be tedious to hunt it down and
then might be CPU/Compiler dependant, e.g. doesn't show up on a Pentium or
other OSs...

-- 
"Tim Nikias v2.0"
Homepage: <http://www.nolights.de>


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From: Slime
Subject: Re: Parse Error?
Date: 10 Oct 2004 19:33:27
Message: <4169c6c7$1@news.povray.org>
> "Parse Error: Singular matrix in MInvers."


The only time I've ever seen that was when I used a matrix <...> transform
on an object and specified a singular matrix.

POV-Ray takes matrix inverses when transformations are made on an object
(because rather than actually transforming objects, it instead transforms
rays with the opposite (inverse) transformations). Singular matrices could
also be caused by scaling a dimension by zero, but those errors are usually
caught early and a "can't scale by 0" error is given.

So... do you have any matrix transformations anywhere?

 - Slime
 [ http://www.slimeland.com/ ]


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From: Tim Nikias
Subject: Re: Parse Error?
Date: 10 Oct 2004 22:14:39
Message: <4169ec8f$1@news.povray.org>
> So... do you have any matrix transformations anywhere?

Uhm, yeah, I guess so: I calculate a planar surface for on-screen layering
using a matrix-transformation applied to a function. As the matrix is based
upon the camera, that might well be the issue. I'll check in on that
tomorrow. Thanks for the pointer, that might really be it.

Regards,
Tim
-- 
"Tim Nikias v2.0"
Homepage: <http://www.nolights.de>


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From: Warp
Subject: Re: Parse Error?
Date: 11 Oct 2004 04:10:37
Message: <416a3ffd@news.povray.org>
JWV <jwv|at|planet.nl> wrote:
> Have no idea what POV-ray needs an inverse matrix for

  How do you think transformations on objects work?

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


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