Answer by jaskij

Do not move the object by means of moving the transform. Instead, modify the speed of the rigidbody (that should be done in the FixedUpdate() method inherited from MonoBehaviour). Preferably by using [Rigidbody.Addforce()][1], although modifying the speed vector directly is also possible should you want to do so (look into [Vector3 Rigidboy.velocity][2]). [1]: http://docs.unity3d.com/Documentation/ScriptReference/Rigidbody.AddForce.html [2]: http://docs.unity3d.com/Documentation/ScriptReference/Rigidbody-velocity.html