After eight years on Unity, RimWorld is running on something else. Ludeon Studios announced in a blog post that update 1.7 moves the colony sim over to Waylith, an engine the studio built itself. According to the developers, the game “looks and plays exactly the same” – the difference is supposed to be purely technical, and a big one at that.
What Waylith changes
Ludeon claims technical performance improvements in the range of 2-4x. In practice, that means:
- faster startup times for the game,
- shorter loading across the board, including map generation and world generation,
- noticeably better behavior in heavily modded setups.
The studio’s own test is the headline number: a late-game colony with 1,500 mods installed needed 14 minutes to load on Unity and just 6 minutes on Waylith. Ludeon does note that your results will depend on how many mods you run and what kind they are, so don’t treat that figure as a guarantee.
How to get update 1.7 right now
On PC, 1.7 currently sits in the unstable Steam branch, so you have to opt into it manually. Save data carries over from 1.6 to 1.7 – and back again, if you decide the Unity version suits you better for now. That makes trying the new engine a fairly low-risk experiment.
What about mods?
Player reports so far suggest most RimWorld mods remain fully functional on Waylith, with the game running roughly twice as fast. Ludeon warns that some older mods may show up in the mod menu with a yellow “potentially unsupported” tag. That isn’t necessarily a broken mod – authors can clear it simply by publishing a version update that flags the mod as 1.7-compatible.
Why it matters for you
An in-house engine means Ludeon no longer depends on someone else’s technology when it wants to optimize load times or memory handling. For a game whose community routinely stacks hundreds of mods on top of each other, cutting loading times in half is arguably the most practical kind of update there is. If you want to keep track of what’s coming next, we collect everything in our RimWorld news hub.
FAQ
It’s an engine developed in-house by Ludeon Studios. With update 1.7 it replaces Unity, which had powered RimWorld for the previous eight years.
No. Ludeon states that RimWorld looks and plays exactly the same – the changes are technical, focused on performance and loading times.
Ludeon cites a 2-4x improvement in technical performance. In its own test, a late-game colony with 1,500 mods loaded in 6 minutes instead of 14.
Yes. Save data carries over from 1.6 to 1.7, and also back the other way if you return to the Unity build.
Older mods can be marked as “potentially unsupported” in the mod menu. The author only needs to publish a version update marking the mod as 1.7-compatible to remove it.