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RimWorld Drops Unity for Its Own Waylith Engine in Update 1.7
Ludeon Studios is moving RimWorld from Unity to its in-house Waylith Engine with Update 1.7, now on the Steam beta branch, claiming 2-4x faster performance.
RimWorld is leaving Unity. Ludeon Studios has moved its colony sim onto its own in-house engine, the Waylith Engine, with the Update 1.7 beta announced on October 12, 2026. The studio says the game "looks and plays exactly the same," while performance improves by "2-4x" in its own tests.
What was announced
Ludeon's blog post, "Announcing the Waylith Engine and Update 1.7," says the update "moves RimWorld from Unity to the Waylith Engine, our own in-house engine built by Ludeon Studios." The change is currently on the unstable beta branch on Steam, and the main branch stays on version 1.6 for now, according to the SteamDB patch notes for the update.
Ludeon tested a late-game colony and reported 2.2x better performance on 1.7 than on 1.6. It also said a modpack of about 1,500 mods went from 14 minutes to 6 minutes to load, though it warned that results "may vary due to your specific PC or mods." Those figures come from the studio's own tests and have not been independently benchmarked.
Ludeon also teased that it is working on something new built on the Waylith Engine, but gave no title, platform or timeline.
Key details
- Developer: Ludeon Studios
- Game: RimWorld, PC (Steam)
- Engine change: Unity replaced by the in-house Waylith Engine
- Update: 1.7, currently on the unstable Steam beta branch
- Performance: 2-4x improvement claimed by Ludeon; 2.2x in one late-game colony test
- Saves and mods: Ludeon says "Your 1.6 savegames will load on 1.7," and that 1.7 saves also work if you go back to 1.6
- Missing or unconfirmed: A full release date for 1.7 on the main branch, the name or platform of the new Waylith game, and a full list of mods that may not work. Very old PCs may have problems with the update, according to GamingOnLinux. Anecdotal Reddit reports cited by PC Gamer describe high memory use, with 12-13 GB of RAM at startup.
What it means for developers
- Custom engines are still a real option. Ludeon has replaced the engine under a mature, long-running game rather than starting a new project, and it says the game looks and plays the same afterward.
- Save and mod compatibility is the hard part. Ludeon's emphasis on saves loading in both directions shows how much players depend on stability. Plan the same guarantees before changing your own engine.
- Measure before you migrate. The 2-4x claims come from controlled tests on specific colonies and mod loads. Benchmark your own game's hot paths before you decide an engine switch is worth the cost.
- Keep an eye on the beta branch. Ludeon's beta-first rollout gives modders and players time to report problems before the main branch moves to 1.7.
- Engine ownership is a strategic choice. Owning the engine lets a small studio tune performance and plan its next game around one technology, but it also means maintaining that technology for years.
Sources
Cover image: © Ludeon Studios.
