RimWorld Ditches Unity for Waylith Engine: 2-4x Faster, Mods Still Work

Ludeon Studios is moving RimWorld from Unity to its own in-house Waylith Engine with update 1.7. The studio says performance improves by roughly 2-4x, existing mods keep working, and 1.6 saves carry over. A beta is already live on Steam.

Ludeon announced the switch in a Steam update, stating that the game will "look and play exactly the same" after the move. The gains are meant to show up almost everywhere: the studio promises "faster startup time, game load time with big mod lists, map generation, world generation, general ticks-per-second, and just about everything else."

Big modpacks load far faster

Ludeon gave one concrete example: "a modpack with 1500 mods went from 14 minutes to 6 minutes to load." That alone would matter to a community that leans heavily on mods, but the more surprising detail is compatibility. Despite the engine swap, community mods should still function. Some may be flagged as "potentially unsupported" because the game version number changes, but Ludeon says they will work just the same.

Saves from 1.6 can also be loaded in 1.7, so nobody loses a colony just by updating.

Beta available now, with caveats

Players and modders can test 1.7 through Steam's beta branch before the official release. Feedback on the announcement's Reddit thread suggests the update mostly delivers: users report better performance and working mods. Some also note that RAM usage has gone up noticeably.

Older hardware may be a problem. The announcement warns that "if your PC is more than 10 years old, 1.7 may not run on it." Anyone on a machine that age should check the beta before the full release arrives.

Another Unity exit

RimWorld is not the first game to leave Unity. Mega Crit moved Slay the Spire 2 from Unity to Godot after Unity tried to introduce a per-installation fee for developers, a plan that was later reversed. Ludeon's reasons are framed around performance rather than licensing, but the result is the same: one more indie project running on an engine its developers control, or at least one free of a commercial engine vendor.