I have been trying to find the difference between the two but to no luck minus this:
The primary diff erence between the two representations is that a quaternion’s axis of rotation is scaled by the sine of the half angle of rotation, and instead of storing the angle in the fourth component of the vector, we store the cosine of the half angle.
I have no idea what
sine of the half angle of rotation
cosine of the half angle
means, could someone explain?