Unity屏幕UI跟随模型移动

public Transform target;   //3D物体
public RectTransform image;    //跟随3D物体的UI
public Canvas canvas;   //UI所在的canvas
private Vector2 screenPos;
private Vector3 mousePos;
void Update()
{
    
    
 	screenPos = Camera.main.WorldToScreenPoint(target.position);
 	if (RectTransformUtility.ScreenPointToWorldPointInRectangle(image, screenPos, canvas.worldCamera, out mousePos))
 	{
    
    
            image.position = mousePos;
    }
}