# Quaternions - rotations

Hi! I just wanted to pop up here with a quick suggestion. I’m trying to learn quaterions, and in both books I’m using, quaterions start off being defined as a vector [q0, q1, q2, q3] where q0 is the scalar part and q is a vector in R3 space = iq1 + jq2 + kq3.

q = q0 + q

So your suggestion is a decent one, I think, I’d just use real names (q0…q3) and not silly ones. Just give a read on the :
http://wiki.jmonkeyengine.org/doku.php/jme3:quaternion?s[]=quaternion
It will give you a good introduction of how to input/get angles from quaternions.
Also look at other docs like : http://wiki.jmonkeyengine.org/doku.php/jme3:math_for_dummies

Yeah, just treat quaterions as a black box that represents orientation. Calling the parameters w, x, y and z has caused nothing but confusion. They are definitely not a vector of Euler angles with some weird w parameter you can figure out later.

All you really need is a basic understanding of what functions to use: http://developerblog.myo.com/quaternions/

IMHO, one of the best introduction to quaternion (usage)

Youtube: playlist : MFGD - Quaternions

MFGD: Math For Game Developer (inlcudes other subject)

And if you want to debug, see value quaternion in 3D spaces: you can use blender, create a object (Empty > axis), change it’s rotation to quaternion mode, set the value.