Re: CALayer transform, setting the Y value of rotation causes side-effects
Re: CALayer transform, setting the Y value of rotation causes side-effects
- Subject: Re: CALayer transform, setting the Y value of rotation causes side-effects
- From: David Duncan <email@hidden>
- Date: Mon, 14 Jul 2008 11:35:43 -0700
On Jul 14, 2008, at 9:57 AM, John Clayton wrote:
Huh?
Question 1: Why do X and Z get very close to PI?
Question 2: Why does Y end up being 1.02 when I set it to 2.12041?
Does anyone know what's going on here? I'm a little stumped by this
one.
The simple answer is that with a 4x4 rotation matrix, there are a
number of distinct matrices that are mathematically equivalent. Note
that 3.14 - 2.12 = 1.02 and that X & Z were flipped 180 degrees.
Effectively your seeing the solver for reversing an arbitrary 4x4
matrix into x/y/z rotations making certain simplifying assumptions
that don't match what you are expecting.
--
David Duncan
Apple DTS Animation and Printing
email@hidden
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