# FreezeRotationX

> Freeze rotation along the X-axis.

## Definition

* **Type:** Field
* **Namespace:** [UnityEngine](/engine/6000.0/script-reference/unityengine.md)
* **Assembly:** UnityEngine.PhysicsModule

```csharp
FreezeRotationX = 16
```

### Examples

```csharp
//This example shows how RigidbodyConstraints is used to freeze the position and rotation of a Rigidbody in the x axis at start-up.
//It also shows what happens when these constraints are removed, when you press the space key
//Attach this to a GameObject with a Rigidbody to see it in action

using UnityEngine;

public class Example : MonoBehaviour
{
    Rigidbody m_Rigidbody;
    Vector3 m_XAxis;

    void Start()
    {
        m_Rigidbody = GetComponent<Rigidbody>();
        //This locks the RigidBody so that it does not move or rotate in the x axis (can be seen in Inspector).
        m_Rigidbody.constraints = RigidbodyConstraints.FreezePositionX | RigidbodyConstraints.FreezeRotationX;
        //Set up vector for moving the Rigidbody in the x axis
        m_XAxis = new Vector3(5, 0, 0);
    }

    void Update()
    {
        //Press space to remove the constraints on the RigidBody
        if (Input.GetKeyDown(KeyCode.Space))
        {
            //Remove all constraints
            m_Rigidbody.constraints = RigidbodyConstraints.None;
        }

        //Press the right arrow key to move positively in the x axis if the constraints are removed
        if (Input.GetKeyDown(KeyCode.RightArrow))
        {
            //If the constraints are removed, the Rigidbody moves along the x axis
            //If the constraints are there, no movement occurs
            m_Rigidbody.velocity = m_XAxis;
        }

        //Press the left arrow key to move negatively in the x axis if the constraints are removed
        if (Input.GetKeyDown(KeyCode.LeftArrow))
        {
            m_Rigidbody.velocity = -m_XAxis;
        }
    }
}
```