刹车处理

rigid.velocity = Vector3.Lerp(rigid.velocity, new Vector3 (0, rigid.velocity.y, 0) , 0,2f);

private bool brake

brake = Input.GetKey(KeyCode.Space);

按下空格 刹车

update 里面接受键盘wsad的input

dir = Vector3(Input.GetAxis("Horizontal"),0,Input.GetAxis("Vertical"));

1.小球移动  AddForce();方法

private Rigidbody Ball_Rigidbody;

public float force=6f;

private bool stop;

void Start(){

Ball_Rigidbody=GetComponent<Rigidbody>();

}

void Update(){

//获取按键，前后左右移动

private Vector3 direction=new Vector3(Input.GetAxis("Horizontal"),0,Input.GetAxis("Vertical"));

stop=Input.GetKey(KeyCode.Space));

}

void ForceUpdate(){

if(!stop){

Ball_Rigidbody.AddForce(direction*force,ForceMode.Force);

}

else{

Ball_Rigidbody.velocity=vector3.Lerp(Ball_Rigidbody.velocity,new vector3(0,Ball_Rigidbody.velocity.y,0),20;

}

力量模式：

ForceMode.acceleration:只关系加速度

ForceMode.force:关系质量的

ForceMode.impulse:脉冲力，考虑质量，是一瞬间的爆发力

ForceMode.velocitychange:忽略质量，只关系速度