Unreal Engine: How to use Swarm to speed up lightmap baking

Got a spare computer on your LAN sitting idle? Do you wish your lighting bakes wouldn’t take so long? Well, Unreal Engine’s Swarm system allows you to bake lightmaps using computers on your network to share the load and speed up your bakes.

The best place to start is the UE docs themselves. This page contains an introduction to Swarm and tells you how to install the Swarm Coordinator (run this on the machine that will be initiating the bake through the UE editor) and the Swarm Agent (on any machine you’d like to participate in baking).

Unfortunately the docs don’t include all the information you’ll likely need to actually get this going in practice. When trying to set this up myself, I got to the point where everything should have been working and the Coordinator was even showing that my agents were connected, but the remote agents would just not receive any baking tasks. I found this useful post on the UE forums which set me in the right direction. I added my own answer to that thread which contains the settings I used to get it all working for myself.

The part I was missing, and which really surprised me, was that you need to share the project directory and make sure the user on the agent machines can access it. There was no info in the docs about this, and no indication on either the agents or coordinator that this is required!

Happy Swarming!

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