Transform.forward

# [Transform](https://docs.unity3d.com/cn/2019.4/ScriptReference/Transform.html).forward

public [Vector3](https://docs.unity3d.com/cn/2019.4/ScriptReference/Vector3.html) **forward** ;

## 描述

返回一个标准化矢量，它表示世界空间中变换的蓝轴。

以下示例说明如何操作 GameObject 在世界空间中变换的 Z 轴（蓝轴）上的位置。与 [Vector3.forward](https://docs.unity3d.com/cn/2019.4/ScriptReference/Vector3-forward.html) 不同，[Transform.forward](https://docs.unity3d.com/cn/2019.4/ScriptReference/Transform-forward.html) 在移动 GameObject 的同时，还考虑其旋转。

旋转游戏对象时，表示游戏对象的 Z 轴的蓝色箭头也会改变方向。[Transform.forward](https://docs.unity3d.com/cn/2019.4/ScriptReference/Transform-forward.html) 沿蓝色箭头所在的轴 (Z) 移动游戏对象。

要在沿 Z 轴移动 GameObject 时忽略旋转，请参阅 [Vector3.forward](https://docs.unity3d.com/cn/2019.4/ScriptReference/Vector3-forward.html)。

```
using UnityEngine;

public class Example : MonoBehaviour
{
    Rigidbody m_Rigidbody;
    float m_Speed;

void Start()
    {
        //Fetch the Rigidbody component you attach from your GameObject
        m_Rigidbody = GetComponent<Rigidbody>();
        //Set the speed of the GameObject
        m_Speed = 10.0f;
    }

void Update()
    {
        if (Input.GetKey(KeyCode.UpArrow))
        {
            //Move the Rigidbody forwards constantly at speed you define (the blue arrow axis in Scene view)
            m_Rigidbody.velocity = transform.forward * m_Speed;
        }

if (Input.GetKey(KeyCode.DownArrow))
        {
            //Move the Rigidbody backwards constantly at the speed you define (the blue arrow axis in Scene view)
            m_Rigidbody.velocity = -transform.forward * m_Speed;
        }

if (Input.GetKey(KeyCode.RightArrow))
        {
            //Rotate the sprite about the Y axis in the positive direction
            transform.Rotate(new Vector3(0, 1, 0) * Time.deltaTime * m_Speed, Space.World);
        }

if (Input.GetKey(KeyCode.LeftArrow))
        {
            //Rotate the sprite about the Y axis in the negative direction
            transform.Rotate(new Vector3(0, -1, 0) * Time.deltaTime * m_Speed, Space.World);
        }
    }
}
```

另一个示例：

```
using UnityEngine;

// Computes the angle between the target transform and this object

public class Example : MonoBehaviour
{
    public float angleBetween = 0.0f;
    public Transform target;

void Update()
    {
        Vector3 targetDir = target.position - transform.position;
        angleBetween = Vector3.Angle(transform.forward, targetDir);
    }
}
```