[Cst-1b] 99.6.4 Graphics / Mistake in example

[Phebe Mann]

I'm pretty sure that the answer should be 

1) scale by (8, 8, 13)
2) rotate about x-axis by 22.62 clockwise
3) rotate about z-axis by 36.87 clockwise
4) translate by (-1,3,7)

Page 132 is a bit misleading, but Neil has gone thru' the cylinder example
in lecture, and rotate about x by -45 is correct.

Phebe

On Sun, 28 May 2000, M.Y.W.Y.B. wrote:

> Ok, I think I've got it now. I made a mistake yesterday night:
> 
> If you first rotate the standard cone about y and then about x then the
> angles must be:
> 
> 1) y: -13.34
> 2) x: +18.43
> 
> If you do it the way Kevin did it, I think the angles should be:
> 
> 1) y: -22.62
> 2) z: +53.13
> 
> (Kevin: the rotation about y is *clockwise* 22.62 degrees, so it's really
> -22.62 degrees)
> 
> Nathan: I can't figure out how you got 76.66 degrees about z-axis. In the
> reverse transformation that must have been your first rotation, so either
> you rotated the transformed cone onto the xz plane (-53.13 degrees or 126.87
> degrees) or onto the yz plane (36.87 degrees or -143.13 degrees).
> 
> 
> *********************
> 
> In the lecture (page 132) we had the example with the cylinder. The given
> solution was: 
> 
> Rotate about z by -19.47
> Rotate about x by +45
> 
> I am pretty sure it should be -45 degrees about x actually.
> 
> 
> *******************
> 
> Mo
> 
> 
> 
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