Screen World 좌표 변환

using UnityEngine;
using UnityEngine.UI;

public class HudText : MonoBehaviour
{
    public Transform targetTrans = null;
    public Vector3 offset = Vector3.zero;
    Camera uiCamera;

    void Start()
    {
        uiCamera = Camera.main;
    }
    void Update()
    {
        transform.position = uiCamera.WorldToScreenPoint(targetTrans.position + offset);
    }
}

using UnityEngine;
using UnityEngine.UI;

public class HudText : MonoBehaviour
{
    //Target Object
    public Transform targetTrans = null;
    public Vector3 offset = Vector3.zero;

    //Text UI Object
    RectTransform rectTrans;
    RectTransform parentRectTrans;
    Camera uiCamera;

    void Start()
    {
        rectTrans = GetComponent<RectTransform>();
        parentRectTrans = (RectTransform)rectTrans.parent;

        uiCamera = Camera.main;
        var canvasArr = GetComponentsInParent<Canvas>();
        for (int i = 0; i < canvasArr.Length; i++)
        {
            if (canvasArr[i].isRootCanvas && canvasArr[i].worldCamera != null)
            {
                uiCamera = canvasArr[i].worldCamera;
                break;
            }
        }
  
    }

    void Update()
    {
        if (targetTrans != null && rectTrans != null && parentRectTrans != null && uiCamera != null)
        {
            UpdateUiLocalPosFromTargetPos();
        }
    }

    void UpdateUiLocalPosFromTargetPos()
    {
        var screenPos = uiCamera.WorldToScreenPoint(targetTrans.position + offset);
        var localPos = Vector2.zero;
        RectTransformUtility.ScreenPointToLocalPointInRectangle(parentRectTrans, screenPos, uiCamera, out localPos);
        rectTrans.localPosition = localPos;
    }
}