Scenes with netcode in single mode are not reloaded on late connected clients

I'm trying to build up the basic functionality of a multiplayer game with netcode.
However, I still have problems with netcode and understand it properly.

I would like to go directly "in-game" as a host and if a client joins/connects later,
should this also come directly in-game.

Since Netcode takes over the scene management for me, this should be possible via

NetworkManager.SceneManager.LoadScene

. Here is a minimal example:

Code (CSharp):

1.  
2.     public void StartGameAsHost(string profileId)
3.     {
4.         NetworkManager.Singleton.StartHost();
5.  
6.         if (IsServer)
7.         {
8.             NetworkManager.SceneManager.LoadScene("TestMap01", LoadSceneMode.Additive);
9.         }
10.  
11.     }
12.  
13.     public void JoinGameAsClient(string profileId)
14.     {
15.         NetworkManager.Singleton.StartClient();
16.     }
17.  

That works. But only as long as I selected LoadSceneMode.Additive. The client then builds exactly the same scenes. However, if I switch to LoadSceneMode.Single, nothing seems to change on the client after the connect, i.e. no scene is loaded.

My second problem is that I would like to load multiple Additive Scenes, but unlike the local one, I can only load one at a time. Is it not possible to load multiple complementary scenes via network?

Code (CSharp):

1.  
2.     NetworkManager.SceneManager.LoadScene("TestMap01", LoadSceneMode.Additive);
3.     NetworkManager.SceneManager.LoadScene("Gameplay", LoadSceneMode.Additive);
4.    

What can be the reason? Maybe someone can help me?

 

Okay, I found out that using single does work. Nothing was displayed visibly, because the complete replacement of a scene logically deletes all non-DDoL GameObjects on both the server and client side, which in my case meant that there was no camera in the new scene.

However, my second problem with the multiple additive scenes remains

 

Generally speaking it is best to not do anything straight after calling StartHost/Server but rather delay anything (ie load scene) to the usual callback event such as client connected or OnNetworkSpawn.

Similarly I can imagine (just a hunch) that you cannot issue multiple additive scene loads right after another. Instead wait for the „scene was loaded“ callback and then load another scene additively.