NPCs don't move in standalone editor window?

Hey there,

I’m trying to use a simple set up that lets players connect into a lobby and starts the game when all players have told the server that they are ready. When the game is started, about 20 NPCs are spawned and are supposed to do their thing, which is starting to execute their behavior trees.

Everything works absolutely as expected in the editor (one or multiple clients, dedicated server box checked) but things go wrong when I’m trying to run the server and clients standalone (standalone meaning uncooked and launching UE4Editor.exe via the command-line).

The clients get placed into the lobby and the server starts the game when everyone is ready, but the NPCs don’t move. They are spawned and seem to have an effect on the server (the doors they are standing next to are server controlled and are open) but the AI doesn’t seem to run. The clients can see each other and client-related stuff (like doors) works.

What could possibly be wrong?

Clients are launched like this:

"PathToUE\UE4Editor.exe" "Path\Project.uproject" -game

Server is launched like this:

"PathToUE\UE4Editor.exe" "Path\Project.uproject" Mapname -server -log

Is there anything I need to pay attention to regarding AI in multiplayer? Does anyone have any
idea why the issue only occurs when running the content standalone (=what does the editor do

Thanks a lot


Okay, I fixed it. The problem was that the NavMesh wasn’t built when the standalone game launched (the editor always rebuilt it when it opened the project, that’s why the issue never occured when playing in the edtior).

The server log displayed this message:

[2014.11.13-21.23.40:026][  0]LogWorld:Warning: *** WARNING - PATHS MAY NOT BE VALID ***

Additionally, a message about the NavMesh requiring to be rebuilt was displayed in the printed messages at the top of the screen.

Setting the NavMesh to rebuild at runtime fixed the problem - if anyone knows how a NavMesh rebuild at the beginnig of the session could be achieved in another way, I’d be happy to know though :slight_smile: