public Vector3f subtract(Vector3f vec) {
        return new Vector3f(x - vec.x, y - vec.y, z - vec.z);
    }
Subtracts the argument and returns the difference as a new instance. The
current instance is unaffected.

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