On Thu, 18 Oct 2001 01:38:30 +0300, Peter Popov wrote:
>On 17 Oct 2001 16:56:20 -0400, ron### [at] povrayorg (Ron Parker)
>wrote:
>
>>Provided you know it came from a given sequence of scale/rotate/translate
>>operations, the exact operations can indeed be recovered.  However, not
>>every matrix is of that type.
>
>If there's no shearing involved, and the matrix is nonsingular, it
>should do. Or is it not so? I'm just guessing here.

It is so.  It's the shearing that's the problem.  I think even a singular
matrix can be decomposed, but I might be wrong on that.  I did all the
math a few years ago; if anyone cares, I'll see if I can find it and 
repost it.

-- 
#local R=<7084844682857967,0787982,826975826580>;#macro L(P)concat(#while(P)chr(
mod(P,100)),#local P=P/100;#end"")#end background{rgb 1}text{ttf L(R.x)L(R.y)0,0
translate<-.8,0,-1>}text{ttf L(R.x)L(R.z)0,0translate<-1.6,-.75,-1>}sphere{z/9e3
4/26/2001finish{reflection 1}}//ron.parker@povray.org My opinions, nobody else's

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