Andreas,
I have tried before to have the mistakes in The Matrix and Quaternions FAQ
corrected and was unsuccessful since the maintainers never followed through
with the corrections.
Since I have a web site with info about the corrections, people have been
asking me to try again and have pointed me to your site as the current
maintainer of the FAQ.
The problem is outlined at the top of my page:
http://www.sigda.org/Eric/java3d/rotation.htm
Specifically, you will see by inspecting the answer to Q27 and the answer
to Q29 contradict each other. Q27 is correct. The sign on the sine terms
in Q29 is in error.
This results in throwing off the matrices and the algorithm in Q37.
Specifically, the algorithm line which " /* Calculate Y-axis angle */"
appears at the end of should NOT have a negative sign in front of
the asin() term.
My page elaborates on this.
Could you please look into this?
I would gladly elaborate on any aspects of this error.
>Date: Fri, 5 Jan 2001 13:14:30 -0600 (CST)
>From: Peter Yoo <[EMAIL PROTECTED]>
>To: [EMAIL PROTECTED]
>Subject: Matrix and Quaternions FAQ
>
>Eric,
>
>I just read your "Retreiving Correct Rotation Components from
>Transform Matrix" page from your homepage which criticizes the Matrix and
>Quaternions FAQ. This was a good read since I had just gotten finished
>reading the Matrix FAQ itself. However, I couldn't help but notice that
>the link that you have to the FAQ seems to be outdated. Apparently FAQ
>ownership has moved onto an Andreas Junghanns. Here is the web address:
>
>http://www.cs.ualberta.ca/~andreas/math/matrfaq_latest.html
>
>The changes that you prescribe haven't been made to the newer FAQ either.
>I haven't checked the math on either page but you might want to get in
>touch with Andreas about editing the FAQ if you're sure it's in error. It
>could help out a lot of people that use the FAQ as a reference.
>
>-Peter Yoo
***********************************************************************
Eric Reiss
Manager MEMS Lab
Swanson New Product Incubator
School of Engineering - University of Pittsburgh
3700 O'Hara Street
647 Benedum Hall
Pittsburgh, PA 15261
Phone: 412-624-9696
Email: [EMAIL PROTECTED]
http://www.sigda.acm.org/Eric/
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