Multiple Scenes and persistent GameObjects

I am starting to add multiple scenes to my project.

How should I handle 'cross' scene objects, like the hero, camera, gamemanager, etc?
I was planning to mark them Object.DontDestroyOnLoad. but what about during design time...

I want them in the scene during design time, so I can quickly playtest each scene as it is built.

Should I just have them in each scene and then mark them as inactive, except in the first one, when doing a final build?

Just wondering what the "standard approach" is for this....

Thanks for any feedback

 

On the object you want to live between scenes just add a MonoBehaviour that keeps a static reference to itself. If the static instance is null in Awake the set the reference to the object, otherwise just destroy it.

Code (CSharp):

1. public class GameManager : MonoBehaviour
2. {
3.     private static GameManager s_Instance = null;
4.  
5.     void Awake()
6.     {
7.         if (s_Instance == null)
8.         {
9.             s_Instance = this;
10.             DontDestroyOnLoad(gameObject);
11.  
12.             //Initialization code goes here[/INDENT]
13.         }
14.         else
15.         {
16.             Destroy(gameObject);
17.         }
18.     }
19. }