Quaternions and rotation vector.

[pjhphysics]

Hi,
I'm trying to calculate a normalized 3d vector representing the quaternion's orientation. Can anyone give me a hand?
Thanks!

 

[lpetrich]

It's easy. Take the vector part of the quaternion and then normalize it.

 

[pjhphysics]

What constitutes the vector part of the quaternion?

 

[Goongyae]

He means use the imaginary elements associated with i, j, and k of course.

BTW, technically a quaternion is itself a vector, since it's a member of a vector space.

 

[lpetrich]

A quaternion can be expressed as

q = q0 + q1*i + q2*j + q3*k

It's a 4-vector, (q0,q1,q2,q3) that can be decomposed into a scalar part, q0, and a 3-vector part (q1,q2,q3).