Hi,
Do u know an algorithm to convert a matrix to a quaternion?
Only orthogonal matrix A can be converted.
You have to find vector v=<x,y,z> such that
Av=v, | |v| | =1
So A is a rotation around v.
You have to find angle (alpha) of rotation.
Quaternion you want to find is given by:
q=< cos(alpha/2.),
xsin(alpha/2.),
ysin(alpha/2.),
z*sin(alpha/2.)>