On Tue, 22 Aug 2000 10:21:49 -0500, Chris Huff wrote:
>Ouch, I often rotate after translating or alternate rotation and 
>scaling...I don't think this would work well. And how does it deal with 
>things like rotations around an arbitrary axis? (which is a transform I 
>have considered adding)

Provided that no skewing took place (that is, that you get three orthogonal 
vectors when you transform three orthogonal vectors) it deals quite well.
It just doesn't give you the results you may have expected.  

For example, 

translate x rotate 45*y 

is equivalent to 

rotate 45*y translate <sqrt(.5),0,-sqrt(.5)>

Similarly, 

rotate 45*y around_point x // if such a syntax existed

would be equivalent to

rotate 45*y translate <1-sqrt(.5),0,sqrt(.5)>

BTW, the transform you mentioned would probably be better implemented as 
a macro, but I think it's been done.

-- 
Ron Parker   http://www2.fwi.com/~parkerr/traces.html
My opinions.  Mine.  Not anyone else's.

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