public Vector3f mult(Vector3f v) {
        return mult(v, null);
    }
Rotates the argument vector and returns the result as a new vector. The
current instance is unaffected.

<p>The quaternion is assumed to be normalized (norm=1). No error checking
is performed; the caller must ensure that the norm is approximately equal
to 1.

<p>Despite the name, the result differs from the mathematical definition
of vector-quaternion multiplication.

@param v the vector to rotate (not null, unaffected)
@return a new Vector3f
jme3-core/src/main/java/com/jme3/math/Quaternion.java