Problem rotating and object with Quaternion.Lerp

Question

Hey Guys

I have a problem trying to rotate an object around its y axis by pressing the A or D buttons. Whenever i try to rotate it ingame it starts to turn around randomly left and right on its y axis. What did i do wrong in this code ?

*edit: The Object needs to turn exactly 60 degrees on a button press and then stop.

Thanks in advance for your help ! :)

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class Camerascript : MonoBehaviour
 {
     Quaternion targetrotation;
     float speed = 1.0f;
 
     private void Update()
     {
         if (Input.GetKeyDown(KeyCode.A))
         {
             targetrotation = GameObject.Find("CameraPivotPoint").transform.rotation;
             targetrotation.y -= 60f;
             Debug.Log("targetrotation " + targetrotation);
         }
 
         if (Input.GetKeyDown(KeyCode.D))
         {
             targetrotation = GameObject.Find("CameraPivotPoint").transform.rotation;
             targetrotation.y -= 60f;
             Debug.Log("targetrotation " + targetrotation);
         }
         GameObject.Find("CameraPivotPoint").transform.rotation = Quaternion.Lerp(GameObject.Find("CameraPivotPoint").transform.rotation, targetrotation, Time.deltaTime * speed);
     }
 }

Answer 1

Best Answer

Answer by Hellium · Dec 05, 2017 at 02:05 PM

Unity uses Quaternions to handle rotation. You should not change the values of the x, y, z or w values directly if you don't know the mathematics behind quaternions.

Here is how I would do it:

  using System.Collections;
  using System.Collections.Generic;
  using UnityEngine;
  
  public class Camerascript : MonoBehaviour
  {
      float speed = 1.0f;
      private Transform cameraPivotPoint ;
      private Quaternion targetrotation;
  
      private void Start()
      {
          cameraPivotPoint = GameObject.Find("CameraPivotPoint").transform ;
      }
  
      private void Update()
      {
          if (Input.GetKeyDown(KeyCode.A))
          {
              targetrotation = Quaternion.Euler( 0, -90, 0 ) * cameraPivotPoint.rotation;
              Debug.Log("targetrotation " + targetrotation.eulerAngles );
          }
  
          if (Input.GetKeyDown(KeyCode.D))
          {
              targetrotation = Quaternion.Euler( 0, 60, 0 ) * cameraPivotPoint.rotation;
              Debug.Log("targetrotation " + targetrotation.eulerAngles);
          }
          cameraPivotPoint.rotation = Quaternion.Lerp(cameraPivotPoint.rotation, targetrotation, Time.deltaTime * speed);
      }
  }

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pascal281 · Dec 05, 2017 at 03:38 PM 0

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Thanks a lot for your help !

There was just a little issue with your script. Whenever the user presses a button twiche too fast, the rotation would get messed up. I fixed this by prohibiting input for 0.6 secounds after the function Get$$anonymous$$eyDown() was called.

Just in case anyone else ever needs that code:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class Camerascript : $$anonymous$$onoBehaviour
 {
     float speed = 20.0f;
     private Transform cameraPivotPoint;
     private Quaternion targetrotation;
     private bool rotationisfinished = true;
 
 
     private void Start()
     {
         cameraPivotPoint = GameObject.Find("CameraPivotPoint").transform;
     }
 
     private void Update()
     {
         if (Input.Get$$anonymous$$eyDown($$anonymous$$eyCode.A) && rotationisfinished)
         {
             targetrotation = Quaternion.Euler(0, +60, 0) * cameraPivotPoint.rotation;
             rotationisfinished = false;
             StartCoroutine(Timer());
         }
 
         if (Input.Get$$anonymous$$eyDown($$anonymous$$eyCode.D) && rotationisfinished)
         {
             targetrotation = Quaternion.Euler(0, -60, 0) * cameraPivotPoint.rotation;
             rotationisfinished = false;
             StartCoroutine(Timer());
         }
 
         cameraPivotPoint.rotation = Quaternion.Lerp(cameraPivotPoint.rotation, targetrotation, Time.deltaTime * speed);
     }
 
     IEnumerator Timer()
     {
         yield return new WaitForSeconds(0.6f);
         rotationisfinished = true;
     }
 }

Answer 2

Answer by InjustticeGaming · Dec 05, 2017 at 01:31 PM

They way I would do it is with a Rigidbody. Nice and easy to use.

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class Test : MonoBehaviour {
     float rotateSpeed = 50f;
     Rigidbody rb;
 
     void Start(){
         rb = GetComponent<Rigidbody> ();
         rb.constraints = RigidbodyConstraints.FreezeRotationZ | RigidbodyConstraints.FreezeRotationX;
         rb.angularDrag = 3f;
         rb.useGravity = false;
     }
 
     void FixedUpdate(){
         Turn ();
     }
 
     void Turn(){
         if (Input.GetKey (KeyCode.A)) {
             rb.AddTorque (new Vector3 (0, rotateSpeed, 0));
         }
         if (Input.GetKey (KeyCode.D)) {
             rb.AddTorque (new Vector3 (0, -rotateSpeed, 0));
         }
     }
 }

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