Transform.up

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

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

## 描述

世界空间中变换的绿轴。

操作游戏对象在世界空间中变换的 Y 轴（绿轴）上的位置。与 [Vector3.up](https://docs.unity3d.com/cn/2019.4/ScriptReference/Vector3-up.html) 不同，[Transform.up](https://docs.unity3d.com/cn/2019.4/ScriptReference/Transform-up.html) 在移动游戏对象的同时，还考虑其旋转。

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

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

```
using UnityEngine;

public class Example : MonoBehaviour
{
    Rigidbody2D m_Rigidbody;
    float m_Speed;

void Start()
    {
        //Fetch the Rigidbody component you attach from your GameObject
        m_Rigidbody = GetComponent<Rigidbody2D>();
        //Set the speed of the GameObject
        m_Speed = 10.0f;
    }

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

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

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

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