Dominik Smith posted to the Ultima Dragons Facebook group about a week ago with something he’s worked on for over a decade. He calls it the Ultima Online Ecosystem Project, an attempt to bring back the virtual ecology that Ultima Online tried out in its alpha test and dropped before release:

Basically, I wanted to bring the virtual ecology that was part of the Ultima Online alpha test back into the game. I now have a little test server set up, where it runs.

The idea, as old players will remember, was that herbivores would graze, carnivores would hunt the herbivores, and populations would rise and fall on their own. As the project’s site puts it, the system was “eventually removed during beta testing and never made it into the released game.” Dominik’s version treats every plant and animal as its own entity, with its own needs and life cycle. Trees, flowers and mushrooms each grow and spread in their own way, depending on the terrain around them. Sheep wander about eating whatever is growing, and timber wolves hunt the sheep. Nothing just appears on a timer at a fixed spawn point.

Getting that to run took a lot of work under the hood. Dominik says he “had to rewrite huge chunks of RunUO/ServUO”, the open-source UO server emulators, and rework the pathfinding along the way. He says the result can simulate something like 400,000 plants and several thousand animals “comfortably” on a modest server with four CPU cores and 8 GB of RAM.

As the original developers found out, the hard part is keeping the system in balance:

I must say, it was surprisingly hard to get a half-way stable ecosystem. Right now the only animals I have are sheep and timberwolves, with a simple predator-prey relationship, and huge population swings are still frequent. There is a ton of finetuning involved.

You can see those swings for yourself. The site has a live Grafana dashboard that charts the populations as they change.

The test server is open to the public, and user accounts are created automatically. You’ll need the current client from uo.com, as well as Razor or ClassicUO, plus a modified set of mul files that takes the static plants off the map.

Dominik notes that this is all “purely a test run,” and he wipes the server often. So far nothing in this Britannia has eaten an adventurer, at least not yet. Details, downloads and the dashboard are all on the project’s website.