From: Myunggi Yi (myunggi_at_gmail.com)
Date: Thu Jan 25 2007 - 16:11:12 CST

Dear VMD users,

I'm trying to calculate my protein's rotation angles
by measuring transformation matrix.

I can extract the matrix elements using
"[measure fit $sel $ref]".

Then how can I decompose these elements to
the rotation angles.
The first 3 x 3 matrix elements represent the rotation matrix,
and the fourth column and row are for the translation.

In what order are these rotations composed (or matrices producted)?
Like Euler rotation matrix ?

A(alpha, beta, gamma) = R_z(gamma)R_y(beta)R_z(alpha)

where, alpha, beta, and gamma are the angles for rotation
around z, y, and z axis.

Where can I get the information for this?

-- 
Best wishes,
MYUNGGI YI
==================================
KLB 419
Institute of Molecular Biophysics
Florida State University
Tallahassee, FL 32306
Office: (850) 645-1334
http://www.scs.fsu.edu/~myunggi