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29 Jul 2024 02:19:47 EDT (-0400)
  Transforming Objects with a Matrix (Message 1 to 8 of 8)  
From: J  Diehl
Subject: Transforming Objects with a Matrix
Date: 11 Jun 2003 09:55:01
Message: <web.3ee733dbf3c076d14fbaca0c0@news.povray.org>
Is it possible to transform any object (or group of objects) by a 3x3 or 4x4
matrix in POV SDL?
I wrote a realtime application about steeringbehaviors in 3D space (Open GL)
and now I want to be able to export movements to POV to create
photorealistic animations (polygon models will be reset by predefined POV
objects). My program handles transformations with matrices. So a function
that works like the camera's look-at would do the trick (the matrix stores
the up-, right- and direction-vector).
Any Idea?


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From: ABX
Subject: Re: Transforming Objects with a Matrix
Date: 11 Jun 2003 09:58:31
Message: <e6deev0od0mpml3jgni3l8bmknm66andft@4ax.com>
On Wed, 11 Jun 2003 09:51:23 EDT, "J. Diehl" <j.d### [at] firemailde> wrote:
> Is it possible to transform any object (or group of objects) by a 3x3 or 4x4
> matrix in POV SDL?

What about looking into documentation for keyword 'matrix'?
http://www.povray.org/search/?s=matrix

ABX


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From: sascha
Subject: Re: Transforming Objects with a Matrix
Date: 11 Jun 2003 11:48:32
Message: <3ee74f50$1@news.povray.org>
rtfm is always a good idea, however, in this case the manual says:
	
6.3.1 Transformations

The supported transformations are rotate, scale, and translate.

but should read

The supported transformations are rotate, scale, translate and matrix.

[Not very advanced, though...]

:-)


ABX wrote:
> On Wed, 11 Jun 2003 09:51:23 EDT, "J. Diehl" <j.d### [at] firemailde> wrote:
> 
>>Is it possible to transform any object (or group of objects) by a 3x3 or 4x4
>>matrix in POV SDL?
> 
> 
> What about looking into documentation for keyword 'matrix'?
> http://www.povray.org/search/?s=matrix
> 
> ABX


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From: ABX
Subject: Re: Transforming Objects with a Matrix
Date: 11 Jun 2003 11:57:02
Message: <01keevo266rnodnnbl5os6okb5v6097rrd@4ax.com>
On Wed, 11 Jun 2003 17:48:31 +0200, sascha <sas### [at] userssourceforgenet>
wrote:
> rtfm is always a good idea, however, in this case the manual says:
> 6.3.1 Transformations
> The supported transformations are rotate, scale, and translate.
> but should read
> The supported transformations are rotate, scale, translate and matrix.
> [Not very advanced, though...]
> :-)

It says correct IMO. Imagine I have baloon. I can do following transformations:
a) rotate it turning around
b) translate it by moving
c) scale it with blowing
but I can't matrix it becouse there is no transformation 'matrix' in reality,
though matematically I can describe this transformations with matix and that's
what is written in next sentence "A transformation matrix may also be used to
specify complex transformations directly." :-)

ABX


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From: J  Diehl
Subject: Re: Transforming Objects with a Matrix
Date: 11 Jun 2003 13:25:01
Message: <web.3ee7653e7beff2cefed43e8b0@news.povray.org>
Thanks. Sorry, I was sure that matrix transformation is not supported by pov
(never read about it before), so I didn't search it in the documentation.
Now it will be easy :)
'bye


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From: Micha Riser
Subject: Re: Transforming Objects with a Matrix
Date: 11 Jun 2003 15:55:19
Message: <3ee78926@news.povray.org>
ABX wrote:

> On Wed, 11 Jun 2003 17:48:31 +0200, sascha
> 
> It says correct IMO. Imagine I have baloon. I can do following
> transformations: a) rotate it turning around
> b) translate it by moving
> c) scale it with blowing
> but I can't matrix it becouse there is no transformation 'matrix' in
> reality, though matematically I can describe this transformations with
> matix and that's what is written in next sentence "A transformation matrix
> may also be used to specify complex transformations directly." :-)

Maybe 
d) an arbitrary *affine transformation* specified by a matrix
would be the correct terminology.

- Micha


-- 
POV-Ray Objects Collection: http://objects.povworld.org


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From: Tim Attwood
Subject: Re: Transforming Objects with a Matrix
Date: 12 Jun 2003 02:03:19
Message: <3ee817a7$1@news.povray.org>
ABX wrote:

>On Wed, 11 Jun 2003 17:48:31 +0200, sascha <sas### [at] userssourceforgenet>
>wrote:
>  
>
>>rtfm is always a good idea, however, in this case the manual says:
>>6.3.1 Transformations
>>The supported transformations are rotate, scale, and translate.
>>but should read
>>The supported transformations are rotate, scale, translate and matrix.
>>[Not very advanced, though...]
>>:-)
>>    
>>
>
>It says correct IMO. Imagine I have baloon. I can do following transformations:
>a) rotate it turning around
>b) translate it by moving
>c) scale it with blowing
>but I can't matrix it becouse there is no transformation 'matrix' in reality,
>though matematically I can describe this transformations with matix and that's
>what is written in next sentence "A transformation matrix may also be used to
>specify complex transformations directly." :-)
>
>ABX
>  
>
(6.3.1.4  Matrix Keyword)
... the matrix command allows more general transformation effects like 
/shearing/. The following matrix causes an object to be sheared ...

The manual could be changed to make this clearer

6.3.1  Transformations
The supported transformation modifiers are |rotate|, |scale|, 
|translate|, and matrix. They are used to turn, size and move an object 
or texture. A transformation matrix may also be used to specify complex 
transformations directly.

This would clear up the meaning of "may also be used" (for complex 
transformations) instead of (is also supported).

Tim Attwood


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From: ABX
Subject: Re: Transforming Objects with a Matrix
Date: 12 Jun 2003 02:40:11
Message: <qq7gev8nnbtnf8417qla8mdq52o5u8mubv@4ax.com>
On Wed, 11 Jun 2003 23:04:47 -0700, Tim Attwood <tim### [at] worldnetattnet>
wrote:
> ... the matrix command allows more general transformation effects like 
> /shearing/. The following matrix causes an object to be sheared ...

http://www.cs.berkeley.edu/~ug/slide/pipeline/assignments/as5/transforms3d.shtml#shear_rot_scale_rot_scale

ABX


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