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Multiple in-editor 'offline' windows for easier multiplayer development.

(Note: I’m just using blueprints)
Currently I’m facing massive frustrations with testing multiplayer in Unreal Engine.
It’s really great to be able to have multiple windows open up for multiplayer testing, but currently I’m spending more time attempting to ‘hack in’ all of the data that would be setup upon manually joining a connection (and so far failing because it’s practically impossible-and would be completely impossible in other projects), just so I can try and test and debug multiplayer in the editor because of the way it forces a window to automatically become the listen server.
I really don’t want to have to be constantly waiting for my project to build every time I need to test some area of multiplayer, to then not even be able to debug it and just guess where issues might be, and then have to rebuild it again to see if my change solved the issue.
I’ve attempted manually disconnecting with console commands but this just causes the project to crash.
Is this something we can possibly hope for in the future? I can’t think of any situation where it automatically starting in the multiplayer session would be helpful so I really hope changes to this can be made.

Have you tried setting the client count in the extra options of the play button?

As mentioned that just forces an automatic connection with a listen server/client relationship, you can’t start up multiple clients in offline mode and then connect manually.
For example if you have a project where you want to customize your characters appearance and name before joining a networked match, there’s no way to test this functionality in the editor because it forces a hosted/connected relationship. And if you wanted to test how to handle disconnections with the additional nodes I’ve heard have made it into 4.6, you still won’t be able to test this in the editor because it crashes if you try to manually force a disconnection.
So currently if you actually want to test a multiplayer game, for most situations unless you have a very small and limited multiplayer project choosing to start with multiple clients in the editor is pointless. It would be infinitely more helpful if it started the client in offline mode so you could test how your project handles connecting/disconnecting players and setting up data like trying to choose a game mode or map and sending players to it. Right now you still need to compile the project and run multiple clients on your computer manually without the benefit of being able to debug blueprints etc.

I have found a solution to this. ProcessExplorer shows you all parameters a program was opened with. So I started a normal standalone game and copied the parameters.
To have 2 independent local game clients you can run this in cmd. You can even debug blueprints in the editor.


C:\Program Files\Epic Games\UE_4.17\Engine\Binaries\Win64\UE4Editor.exe "**%FULLPATHTOPROJECT%**\ProjectName.uproject" -game -PIEVIACONSOLE -ResX=1280 -ResY=720 -Multiprocess -messaging -SessionName="Play in Standalone Game" -windowed GameUserSettingsINI="**%FULLPATHTOPROJECT%**\Saved\Config\Windows\PIEGameUserSettings0.ini" -MultiprocessSaveConfig -MultiprocessOSS WinX=-1912 WinY=31 SAVEWINPOS=1

Edit the parameters accordingly.