unity to achieve the object back and forth within a certain rotation angle range

 1 using System.Collections;
 2 using System.Collections.Generic;
 3 using UnityEngine;
 4 
 5 public class Rotate : MonoBehaviour {
 6     private float origionZ;
 7     private Quaternion targetRotation;
 8     public float RotateAngle = 60;
 9     public int count = 0;
10     private bool i;
11     // Use this for initialization
12     void Start () {
13         origionZ = transform.rotation.z;
14     }
15     
16     // Update is called once per frame
17     void Update () {
18         if (Input.GetKeyDown(KeyCode.D))//当按下D时进行旋转
19         {
20             if (count >= 3)
21             {
22                 i = false;
23             }
24             if (count <= 0)
25             {
26                 i = true;
27             }
28             
29             if (i == true)
30             {
31                 count++;
32                 targetRotation = Quaternion.Euler(0, 180, RotateAngle * count + origionZ) * Quaternion.identity;
33             }
34             if(i==false)
35             {
36                 count--;
37                 targetRotation = Quaternion.Euler(0,180,RotateAngle*count+origionZ) * Quaternion.identity;
38             }
39             
40 
41         }
42         else
43         {
44             transform.rotation = Quaternion.Slerp(transform.rotation, targetRotation, Time.deltaTime * 2);
45             //避免误差
46             if (Quaternion.Angle(targetRotation, transform.rotation) < 1)
47                 transform.rotation = targetRotation;
48         }
49 
50     }
51 }

Using quaternions avoid gimbal lock problem, and achieves a smooth conversion. When the D key is pressed, z-axis of the object is rotated 60 degrees, in the script, Z-axis object change back and forth between 0 and 180 degrees, wherein the value of count may vary, the result is that the rotation angle range and change the number.

The script may be applied to a subject in need uinty rotation instruction, such as buttons, knobs, doors, and other objects.