화살의 head가 날아가는 방향으로 따라 회전

//01. PlayerFire Script

public GameObject bulletFactory;
public Transform firePos;

private UpdateAttack()
{
	var bullet = Instantiate(bulletFactory);
    
    bullet.transform.position = firePos.position;
    Vector3 dir = target.position - firePos.position;
    bullet.transform.forward = dir + Vector3.up * 10;
}

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//02. Bullet Script

Rigidbody rb;
public float speed = 10;
bool isHit;
Quaternion hitRotation;
Vector3 hitPos;

void Start()
{
	rb = GetComponent<Rigidbody>();
    rb.velocity = transform.forward * speed;
}

void Update()
{
	if(isHit)
    {
    	transform.rotation = hitRotation;
        transform.position = hitPostion;
    }else
    {
    	rb.transform.forward = rb.velocity.normalized;
    }
}