Calculating direction between vectors

[yn97]

How can I calculate the rotation value of a model to look at a position?

I need the Y rotation to rotate the head of tank animated not fast in one step. I need the Y value to use it in this way: public void head_to(float deg) { Quaternion qua = new Quaternion().fromAngleAxis(FastMath.DEG_TO_RAD * deg, new Vector3f(0, 1, 0)); Tween rot = SpatialTweens.rotate(head, head.getLocalRotation(), qua, 1f); anim.add(Tweens.smoothStep(rot)); turning_sound.playInstance(); }