c# - Tracking a game object transform - Why using FindGameObjectWithTag doesn't work? -

i'm following tutorial (precisely survival shooter), , @ stage implement navmesh. original script this:

 transform _player;  navmeshagent nav;   void start()  {      _player = gameobject.findgameobjectwithtag("player").transform;      nav = getcomponent<navmeshagent>();  }   void update()  {      nav.setdestination(_player.position);       } 

so far nothing special. press play , strangely enemy (i have 1 @ moment in scene) reaches initial position of player (0,0,0) instead of following around if player moves. realized position of player not updated in _player field , stays @ 0,0,0.

i tried different approach: dragged , dropped player's game object onto property in ui (i made property public first , changed gameobject). in case works flawlessly:

 gameobject _player;  navmeshagent nav;   void start()  {      //player not retrieved here before, it's passed assigning gameobject property directly through ui      nav = getcomponent<navmeshagent>();  }   void update()  {      nav.setdestination(_player.transform.position);       } 

at stage wonder:

does findgameobjectwithtag method make copy of object instead of returning reference gameobject? why doesn't work in first instance. use unity 5 way.

you have more 1 object tag "player" in scene. changed code detect condition.

transform _player; navmeshagent nav;  void start() {     gameobject[] playerobjects = gameobject.findgameobjectswithtag("player");     if(playerobjects.length>1)      {         debug.logerror("you have multiple player objects in scene!");     }     _player = playerobjects[0].transform;     nav = getcomponent<navmeshagent>(); }  void update() {     nav.setdestination(_player.position);      }