I have some trouble to understand, and handle Quaternion and Vector3. I'm improving the tutorial Tank of Unity:

EDIT: Because a video explain so much better, there is a link to the 30 secondes video I made: https://www.youtube.com/watch?v=nNrmlfbHNTI&feature=youtu.be

In the first part, the turret turn with restriction made with the both line newRotation.z = 0.0f; and newRotation.x = 0.0f; (see code bellow).

In the second part, I just comment this two line.

My probleme is: i want to be able to look up and down (like in the second part of the video, but with a DEPRESSION LIMIT (don't look too much high and too much down)

I try soo manny case and can't manage the thing i want to do... there is the code of the script in ref to the Tank turret:

public float m_TurnSpeed = 8f;
private Transform m_Transform;
private int floorMask;
private float camRayLength = 100f;

void Awake()
    floorMask = LayerMask.GetMask ("Ground");
    m_Transform = GetComponent <Transform> ();

void FixedUpdate()
    Turning ();

void Turning()
    Ray camRay = Camera.main.ScreenPointToRay (Input.mousePosition);
    RaycastHit floorHit;

    if (Physics.Raycast (camRay, out floorHit, camRayLength, floorMask))
        Vector3 playerToMouse = floorHit.point - transform.position;
        Quaternion newRotation = Quaternion.Slerp(m_Transform.rotation, Quaternion.LookRotation(playerToMouse), Time.deltaTime * m_TurnSpeed);

////////// EDIT 2: probleme solved with the following line //////////

        //block totaly Z and X quanta
        //newRotation.z = 0.0f; 
        //newRotation.x = 0.0f;

        m_Transform.rotation = newRotation;

        float tmpX = m_Transform.localEulerAngles.x;
        if (tmpX > 20.0f && tmpX < 90.0f)
            tmpX = 20.0f;
        else if (tmpX < 315.0f && tmpX > 280.0f)
            tmpX = 315.0f;
        m_Transform.localEulerAngles = new Vector3(tmpX , m_Transform.localEulerAngles.y, 0.0f);

Thanks !

  • \$\begingroup\$ Make a video of the problem, put it on youtube, link it here. Easier to understand. \$\endgroup\$
    – Engineer
    Apr 6, 2016 at 12:51

1 Answer 1


Looks like you need to restrict the euler angles of the turret, after the quaternion rotation has been effected. basically you'd just do something like:

transform.localEulerAngles = new Vector3(transform.localEulerAngles.x < 0 ? 0 : transform.localEulerAngles.x, transform.localEulerAngles.y, transform.localEulerAngles.z);

...I think X is the right axis and not sure if it should be < or > and I think 0 rather than 90, 180 or 270. Try variations and you should get results.

  • \$\begingroup\$ It was the good function to look at, after some research, i found the way to sole it, thanks you ! I edit my function. \$\endgroup\$
    – Ugo Hed
    Apr 6, 2016 at 16:38

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