[SOLVED] Changing X rotation changes Y euler angles.

I wrote a script for my car wheels. I try to get Y rotation but if X rotation greater than 90, the Y axis euler angle returns 10 more than I expect.

My code:

using System.Collections;

using System.Collections.Generic;

using UnityEngine;



public class MovementTier : MonoBehaviour

{

    public float speed;



    public float yAngle;



    public GameObject wheel1;

    public GameObject wheel2;



    // Start is called before the first frame update

    void Start()

    { 



    }



    // Update is called once per frame

    void Update()

    {

        yAngle = Vector3.Angle(wheel1.transform.right, Vector3.right);



        Debug.LogWarning(yAngle);



        if (Input.GetKey(KeyCode.LeftArrow) && yAngle < 120f)

        {

            wheel1.transform.Rotate(0, -speed * Time.deltaTime, 0);

            wheel2.transform.Rotate(0, -speed * Time.deltaTime, 0);

        }

        if (Input.GetKey(KeyCode.RightArrow) && yAngle > 50f)

        {

            wheel1.transform.Rotate(0, speed * Time.deltaTime, 0);

            wheel2.transform.Rotate(0, speed * Time.deltaTime, 0);

        }



        //if (!Input.GetKey(KeyCode.RightArrow) && !Input.GetKey(KeyCode.LeftArrow) && yAngle != 90) returnToCenter();

    }



    void returnToCenter()

    {

        Debug.Log("hi");

        if (yAngle < 90)

        {

            if (Mathf.Abs(90 - yAngle) <= 3)

            {

                wheel1.transform.localRotation = Quaternion.Euler(wheel1.transform.localRotation.x, 0, wheel1.transform.localRotation.z);

                wheel2.transform.localRotation = Quaternion.Euler(wheel2.transform.localRotation.x, 0, wheel2.transform.localRotation.z);

            }

            else

            {

                wheel1.transform.Rotate(0, -speed * Time.deltaTime, 0);

                wheel2.transform.Rotate(0, -speed * Time.deltaTime, 0);

            }

        } 

        else if (yAngle > 90)

        {

            if (Mathf.Abs(90 - yAngle) <= 3)

            {

                wheel1.transform.localRotation = Quaternion.Euler(wheel1.transform.localRotation.x, 0, wheel1.transform.localRotation.z);

                wheel2.transform.localRotation = Quaternion.Euler(wheel2.transform.localRotation.x, 0, wheel2.transform.localRotation.z);

            }

            else

            {

                wheel1.transform.Rotate(0, speed * Time.deltaTime, 0);

                wheel2.transform.Rotate(0, speed * Time.deltaTime, 0);

            }

        }

    }

}

Sorry for my grammar mistakes.

 

Yep, this is why Euler angles are terrible. For any given rotation, there are multiple valid Euler angle representations, and the three components of the Euler angle cannot be handled independently. This is a fundamental fact of the math behind Euler angles.

Further reading and examples about avoiding problems that arise from this can be found in this article. The short answer is: don't ever read out the Euler angle value and expect to rely on it.

 

So... What I can do?

 

The article linked contains a lot of examples, and odds are good that one of those will work in your situation. Probably checking with one of the transform.forward or transform.right vectors would be helpful.

 

Thanks, I will look at that.

 

I tried that, it works well with right vectors but I think it isn't best way to do that.

 

What's your code, and what makes you think it isn't the best way to do that?

 

In Unity documents, euler angles is recomended way to do that, am I wrong?

 

I don't know whether the Unity documents say that, but if they do, they're wrong. Euler angles are ideal solution for only one thing, which is letting a human type in rotation values (which is why they're used in the Transform Inspector). For literally everything besides that, you want to use a different solution, or you'll have problems like the one you're seeing.

 

I noticed when I change rotation of parent GameObject, the solution works wrong.

 

In that case you probably should be using .localRotation in place of .rotation.

It's hard to help without seeing the code though

 

I edited code.

 

Sorry, I just missed a point and my problem is solved with Euler Angles.