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Re: Why are transforms 4 x 4? [message #37387]

Mon, 15 December 2003 10:18

profxtjb
Messages: 22
Registered: October 2003

Junior Member

"Karl Schultz" <kschultz_no_spam@rsinc.com> wrote in message news:<vtrldcr3j1gl7d@corp.supernews.com>...
> "Thomas Brueckner" <profxtjb@earthlink.net> wrote in message
> news:52e94d00.0312141710.2a29c8f2@posting.google.com...
>> My geometry knowledge is limited, so I am unsure why IDL uses 4 x 4

> Affine transformations are made up of a linear transformation followed by a
> translation.

> point. So, if you add an additional 4th coordinate to the 3D vector with
> value 1, you can put the translation factors in the 4th row or column of the

Well, shucky darn, Karl, that sounds like a nice, sneaky trick. I can
see how it works.
It must've been invented by a really LAZY programmer! I approve! :)

-Thomas

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		Re: Why are transforms 4 x 4? By: profxtjb on Mon, 15 December 2003 10:18
		Re: Why are transforms 4 x 4? By: Karl Schultz on Mon, 15 December 2003 07:41

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