Quaternion将对象的旋转从from平滑插值到to。一般用于模拟相机的观察方向从物体a过渡到物体b的效果

    public Transform from;

   public Transform to;

     float time; //过渡花费时间

     float startTime;

      void Start(){

        startTime = Time.time;

       }

   void Update(){

       float usedTime = (Time.time-startTime)/time;

       transform.rotation = Quatertion.Slerp(from.rotation,to.rotation,usedTime);

}