RimWorld abandons Unity for its own in-house game engine that more than doubles performance and somehow doesn’t break mods

[u/AsPeHeat]

https://frvr.com/blog/news/rimworld-abandons-unity-for-its-own-in-house-game-engine-that-more-than-doubles-performance-and-somehow-doesnt-break-mods/

[u/Icy_Team_Aokiji]

now thats a performance boost thats worth moving to a new engine

[u/leg00b → u/Icy_Team_Aokiji]

A lot of people are reporting good things, too. I read one user saying their loading time went from 20 mins to like just under 3

[u/SunsetHippo → u/leg00b]

legit, if you had like
40+ mods, you opened the game and went to go make food.

[u/Cynical_Cyanide → u/SunsetHippo]

How ... How is that even possible? Using an SSD, not a potato machine?

Like that's slower than installing an entire large game and booting it up for the first time (if you've got the files on an SSD, of course).

[u/ImCravingForSHUB → u/Cynical_Cyanide]

IIRC Rimworld ran on a single CPU core and reads before loading stuff like a single lane assembly line so everything has to pass through the one very inefficient lane in-game to be checked one by one before it can be loaded one by one which is why even with the fastest read SSD on the market it will take an atrociously long time

Some mods uses dark and forbidden magic to allow Rimworld to use multithreading and it's possible this update basically does that while streamlining and removing the convoluted unneeded functions running in the background that base unity engine came equipped with

[u/Cynical_Cyanide → u/ImCravingForSHUB]

Even if its singlethreaded, unless your cores are garbage, it just shouldn't take that long to load. Rimworld just isn't that catastrophically complicated. Also, the mod authors must be pretty skilled if they're able to figure out how to split threads off the main thread.

[u/Justhe3guy → u/Cynical_Cyanide]

I think they meant go microwave food not actually prep, chop veggies, make a full oven/stove cooked meal from scratch

For me with 400 mods it took 12 minutes on my midrange PC until I added mods that sped up the game and mod loading to about 4 minutes

[u/Icarian_Dreams → u/Justhe3guy]

I've had a modlist with 1.5k mods launching in around 45 minutes at one point. So I was actually preparing dinner sometimes while the game was loading.

[u/Cynical_Cyanide → u/Justhe3guy]

Right but 12 minutes is insane. 20 minutes is what the other guy said, which is more than enough time to install a game and run it!

And it doesn't make sense that MODS can speed up the loading times, like what absolute spaghetti code abomination is so bad that mods can triple load speed? What's being calculated or decompressed or ... whatever?

[u/SunsetHippo → u/Cynical_Cyanide]

I dont know. But thats how it was. 

[u/All_Thread → u/SunsetHippo]

That is absolutely how it was I run 50ish mods with my set up and I get my coffee going while it loads

[u/SunsetHippo → u/All_Thread]

It was just how it was

[u/molporgnier → u/SunsetHippo]

Same as it ever was Same as it ever was.

[u/Mysteoa → u/Cynical_Cyanide]

Not all games can take advantage of an SSD speeds.

[u/Cynical_Cyanide → u/Mysteoa]

If there's a huge load time, then either the bottleneck is loading things, or calculating things. It makes no sense for it to take 20 minutes to calculate things, someone would've had to butcher the code pretty bad.

[u/Shadowex3 → u/Cynical_Cyanide]

Have you ever tried booting terraria with large mods? It's insane how long it takes. And you have to do the entire 10+ minute rebuilding process for every single change.

[u/TealcLOL → u/leg00b]

20 minute loading times?? Do the mods do this? I don't have anything remotely close to that when I play.

[u/Titan3124 → u/TealcLOL]

Sounds like you have space for more mods then lol

[u/Disillusionification → u/TealcLOL]

301 mods currently. On my old laptop that mod list took over 15 minutes. On my new PC it was at least 5 minutes, I think around 7. I never actually timed it, that's just going based off stuff I'd go do while I waited and roughly how long those things take me.

Just tested now and it started in less than 2. Actually insane.

[u/MPolygon]

Kudos to them for upgrading to an entirely new engine without breaking mods or savegames

[u/MaNameMoe → u/MPolygon]

Meanwhile Bethesda manages to break every single mod anytime they update their games

[u/Wadarkhu → u/MaNameMoe]

You leave indie developer Beth Esda alone!

[u/poll262 → u/Wadarkhu]

"I'm Bethany Esda thank you for playing my indie game"

[u/FinAdda → u/Wadarkhu]

Solo dev Beth. Bless.

[u/Mortarious → u/MaNameMoe]

For context there is a mod that fixes this. Yes. It exists and it's free and it fixes script extender with updated game version.

Last time I tried expressing the idea that maybe after 2 decades Bethesda, a multi billion dollar game dev, can figure out how to update their game without breaking mods and people got pissed, said it was impossible or would cost them too much.

People said something similar about archive limit and that got fixed a while ago too

[u/Noobponer → u/Mortarious]

What is that mod called? o.o

[u/40_Thousand_Hammers → u/Mortarious]

Bro aint going to tell what mod it is lmao

[u/alphagusta → u/Mortarious]

The fact the community needs a mod to fix mods breaking if the game version changes by a single decimal point.

[u/BlaBlub85 → u/Mortarious]

Last time I tried expressing the idea that maybe after 2 decades Bethesda, a multi billion dollar game dev, can figure out how to update their game without breaking mods

But how is almighty Todd gona afford another yacht if they spend actual money on improving their tech

[u/ModernistGames → u/MaNameMoe]

Even games that are a decade old...

[u/aimy99 → u/ModernistGames]

I was gonna say "well the original version of Skyrim doesn't get updated" but then I remembered Fallout 4 is 11 years old now...

Oh dear.

[u/MorningFresh123 → u/MaNameMoe]

It’s a lot easier to avoid this when you don’t have (many) humans writing code

[u/AnonD38 → u/MaNameMoe]

They even break things in the update meant specifically to fix the things they've broken previously.

[u/Radarker → u/MaNameMoe]

Yeah, but that was intention. They wanted to break mods.

[u/MilliardoMK → u/MaNameMoe]

It's almost like they're completely incompetent and all terrible at their jobs.

[u/Lurevy → u/MaNameMoe]

“One does not simply update Fallout 4”

[u/caffeinated_WOLF → u/MaNameMoe]

Not only mods, Bethesda breaks vanilla game too. 

[u/CalcipherGaming → u/MaNameMoe]

RSDragonwilds.. oh.. you guys wanted to keep those saves?

[u/_zepar → u/MaNameMoe]

every SKSE plugin*, which are a very very small portion of mods. but they also started showing up a lot in recent times, simply because nexusmods is overrun my vibecoded SKSE plugins. AI can code that for you, but it cant make .esp mods

[u/RiffyDivine2 → u/_zepar]

a RAG can help a lot with mod coding not being crap. I ended up using one for rimworld I built for just making stupid silly mods.

[u/xerillum → u/RiffyDivine2]

It’s good to be wary of AI generated DLLs in Skyrim modding, but nobody has the time to write a shitload of rimworld xmls by hand

[u/atrib → u/MaNameMoe]

Well mods is never the devs responsibility, if it does not break it consider it a bonus rather than an expectation.

[u/MakeBardGreatAgain → u/atrib]

If your game is made with a major intention for it to be modded, you should be an expectation for user satisfaction

[u/barcode_soma → u/MPolygon]

Smooth operators fr

[u/MorningFresh123 → u/MPolygon]

Gee, I wonder how they did it. This seems like something that would’ve been unthinkable previously…

[u/Chainmale001 → u/MPolygon]

Better that Helldivers 2

[u/Datuser14 → u/Chainmale001]

That’s not exactly praise

[u/ephilos → u/MPolygon]

Kudos to Claude

[u/precision_cumshot]

as someone who made the switch yesterday, it’s staggering how well the game runs now. i have a ~200 mod run featuring a 70 person colony with 100+ animals that would run at around 150 TPS (maximum being 360). this update completely restored the game speed to the maximum, with the only hiccup being that i had to uninstall a graphics mod and a handful of performance optimizers for it to properly work.

genuinely a massive step in performance that i couldn’t even dream of. massive props to Ludeon

[u/RiffyDivine2 → u/precision_cumshot]

performance optimizers

All of them are currently broken and likely not needed anymore. There is a thread going in the /r/rimworld on what is working.

[u/zektiv → u/RiffyDivine2]

Thank you. That likely explains why I haven't been able to load in after enabling my mods on 1.7. 

[u/precision_cumshot → u/RiffyDivine2]

i saw a comment that said they’re doing more harm than good with the new updates,so i took them off. i imagine whatever scripts they’re running are interfering with how the new engine runs

[u/NationCrusher → u/RiffyDivine2]

Man I stopped playing because of the amount of mods I needed just for performance

Fine…fine…I’ll replay the war-crime sim (but I’ll be wholesome about it. Everyone gets a table to eat at)

[u/Tartrus]

Apparently some of the engine framework came from the BRUTAL engine developed by Rocketwerkz

[u/aequasi08 → u/Tartrus]

Just the part for interacting with Vulkan. Everything else is home-grown

[u/Hakaisha89]

Kinda expected, rimworld was tickling the edges of what unity could do, which is impressive in its won way.

[u/RiftHunter4]

Today is not a good day for Unity lol. First a major account issue and now this.

[u/Ready-Customer9242]

Good. Unity has become terrible with its current team

[u/Jon-Umber]

Unity still getting fucked by Riccitiello's awful decisions 3 years after they fired him is pretty amusing.

[u/Hurka_Durka → u/Jon-Umber]

Yeah have to wonder how much they've paid Unity over all these years with such a hit game.

[u/AceOfEpix]

Genuinely impressive that they did this without breaking mods or saves. There's still small glimmers of light in the gaming industry after all.

[u/Shootemout → u/AceOfEpix]

a few mods did get broken per some user reports, but i imagine for a game as massive as rimworld there's bound to be some crossed wires during engine changes. impressive nonetheless

[u/T-MoneyAllDey → u/AceOfEpix]

It's crazy what AI is doing to enable small people to do big things

[u/Negitive545 → u/T-MoneyAllDey]

Bot

[u/T-MoneyAllDey → u/Negitive545]

I promise you I'm not lol

[u/Negitive545 → u/T-MoneyAllDey]

Somehow that's worse.

Ludeon is a studio, not a single person, and they don't use AI in their game.

[u/Fake__Duck → u/Negitive545]

Every developer is using AI to some degree nowadays, using ai to help write code and solve bugs is not the same as letting ai vibe code the game from scratch. Its a spectrum

[u/T-MoneyAllDey → u/Negitive545]

https://x.com/TynanSylvester/status/2096979985974124833

Tynan at minimum is using AI to play the game

"Astra can play RimWorld to the credits screen all by itself. This is an inflection point in AI capability."

[u/Initial-Beginning853 → u/T-MoneyAllDey]

You're associating two separate things in an attempt to back into your earlier statement.

Bud - people have been smart and creative since the beginning of time. Yes advancements will happen due to AI but you're making as assumption that new and better MUST be AI.

[u/heydudejustasec → u/T-MoneyAllDey]

If you're not familiar with how twitter/x.com works, that's Tynan showing off somebody else's experiment of having Astra play Rimworld. It's not him doing that.

That being said, we have zero reason to think Rimworld is AI-free or that their next game will be. If anything, an interview from a year ago confirms it's in limited use at Ludeon with programmers, and models at that time were vastly less capable than they are now. We're talking Opus 4.1 💀

[u/thecrius]

Mods interface with the game apis. The game apis are written by the Devs.

This is a true statement valid for any game.

It's not a surprise that a game that thrive because of the incredible modding scene, do a refactor making sure to not break the modding apis.

The surprise is when it happens the contrary, like with the shitty bethesda.

[u/Bgndrsn → u/thecrius]

I feel like this is massively downplaying it LOL

[u/ElCthuluIncognito → u/thecrius]

I think you are underselling how difficult it is though. Yes it’s controlled by the devs, but it’s used essentially arbitrarily by your users, potentially leveraging functionality you didn’t intend or otherwise “forgot” about. To preserve all the behavior all the way down to the core game logic and rendering speaks volumes about the coherence of their initial implementation, attention to detail, or most likely both.

[u/sonicatdrpepper → u/thecrius]

Tbf with Bethesda, their updates actually don't break a majority of mods, they just break stuff that hooks into the game executeable via SKSE, 99% of stuff made using the creation kit doesn't actually break between updates.

[u/coolcosmos → u/thecrius]

APIs are one thing, ABI is another.

[u/Byte11 → u/thecrius]

A team that can make its own game engine likely had the wisdom to create an api thats generic regardless of engine.

[u/zidave0]

Can we get more awesome gaming news like this?

[u/RiffyDivine2]

Mostly doesn't break mods, some are borked like SOS2 unless it's been updated. However hot damn it moved the load time with 500 mods from fifteen minutes to three and a half.

[u/Cold_Market4614]

insane achievement ive never seen before in any other game. props to ludeon

[u/ThatssoBluejay]

Unity bit off more than they could chew

[u/TeamWorkTom]

That's Impressive asf.

[u/Full-Construction680]

Oh, what’s that? You hear that, Bethesda they figured it out. They managed to use a game engine that works increases performance and doesn’t break mods. Gee, I wonder if you could do the same thing

[u/Aggressive_Ask89144]

Holy shit, the latter part of that sentence sounds like black magic 😭. How did they even get it not break any mods?

[u/ziplock9000]

I'm not surprised. I've used Unity to develop about 5-6 games and it very quickly becomes more of a barrier than a tool. It actually slows down development not speed it up due to the house of cards nature of scenes, the way things are stored and referenced.

For my latest project, (which is actually similar to RimWold in many ways) I decided to roll my own engine again after making an older one back in 2005. So far I've got further into the actual game development than I would if I used Unity even when including the extra work of developing the engine alongside. Everything feels like it's set in stone too, not realy to collapse because I tweaked on thing in a file or object somewhere.

I've wasted years on shitty Unity. It caused issues so much that it directly caused projects to fail.

[u/Locky0999]

Maybe this means more people will adhere to godot

[u/TheGrandWhatever → u/Locky0999]

... They didn't switch to godot

[u/burgertanker → u/Locky0999]

This has nothing to do with Godot

Next you'll tell us you're a Linux user 🙄

[u/cool_fox]

if you think no AI was used to do this, boy do I have a bridge to sell you

[u/Efficient-Top-1143 → u/cool_fox]

Despite the down votes you're probably right. I'm not pro-ai by any means but Tynan is a know proponent of it.

[u/hellranger788]

I dont mind AI, but there has to be a balance between it being useful and annoying

[u/Genralcody1]

So they stole unity and fixed it for themselves?

Good

[u/JustHere_4TheMemes]

"Claude, rewrite our game engine in a way that doesn't break mods. I've linked the source code folder."

[u/No-Carrot4267 → u/JustHere_4TheMemes]

"Claude, upgrade this guy's intelligence please. And make him gay"

[u/TheJuggernaut0 → u/JustHere_4TheMemes]

I mean, even if so, it worked. Like you can't call it slop if it objectively works better

[u/gruey → u/TheJuggernaut0]

Eh, that's a trap. Slop would include bad architecture and lack of clarity that hinders future improvement.

I sometimes think AI does this intentionally as a form of job security. No human will ever want to read that..

[u/JaesopPop → u/JustHere_4TheMemes]

Probably not, no.

[u/reebokhightops → u/JustHere_4TheMemes]

“ChatGPT, who is Tynan Sylvester?”

[u/Iamhandsomesorry]

its vibe coded with ai. like theres no way mods doesnt break unless ai is involved. and the speed of the migration just doesnt add up

[u/L1teEmUp → u/Iamhandsomesorry]

Vibecoded or not, the fact that there is performance improvements and mods are not breaking says it all that they are doing the right thing… why against it?

[u/KreateOne → u/L1teEmUp]

People just want any reason to hate AI nowadays. They’ll be disappointed to learn that coders were some of the earliest adopters of AI, and that using AI for coding will only increase in the future. Using AI to generate mostly stolen assets is bad, using AI for coding a new engine for their already popular game, to separate from the toxic company who developed the engine they’ve been using, is a good thing. Most people can’t seem to differentiate between the 2 though, they just see AI and think that translates to stolen assets and uncanny art.

[u/NobodyElseButMingus → u/Iamhandsomesorry]

“AI coding is bad because it checks notes improves performance and stability.”

What are we even doing anymore?

[u/Extreme_Glass9879]

they went from one fps to 2 whole frames.

Maybe they can double their playercount from 0 next

[u/thisistherevolt → u/Extreme_Glass9879]

Moron

[u/Pale_Ad9494]

Officially supporting multiplayer would do way more for the average player than being able to run 1000 mods at a time

[u/SunsetHippo → u/Pale_Ad9494]

This man doesn't Rimworld. At all.
Additional note: Rimworld mutliplayer sounds fun, but these are games that could last DAYS. With hours of just "nothing going on".

[u/Sprinkle_In_Hole → u/SunsetHippo]

My buddies and I use Rinworld Together with a small mod list of about 20 and it's been a blast

[u/Teftell → u/Sprinkle_In_Hole]

Yes, playing such a game in a duo is a blast

[u/Teftell → u/SunsetHippo]

The mod is there and it worked really well, so the official multiplayer functionality should also be possible. Also, Factorio, Civ, Terraria, Minecraft, Valheim are also right there, games last comparably long. Also, hours of nothing happening in RimWorld is just not true.

[u/GlorifiedBurito → u/Teftell]

Possible but not necessary. The mods already exist and work well. Why bother building and maintaining multiplayer when it already exists?

[u/SunsetHippo → u/GlorifiedBurito]

Exactly. Let it stay a mod. Its more baggage that most people probably will never touch.

[u/Teftell → u/GlorifiedBurito]

Because such multiplayer would be inherently more stable and convenient

[u/GlorifiedBurito → u/Teftell]

Would it though?

[u/Immediate-Sink-8494 → u/Teftell]

How so?

[u/BlueTemplar85 → u/Immediate-Sink-8494]

Well, for instance these MP mods are usually not using the latest (major !) RimWorld version, with all the annoyances that this brings.  

(Like being forced to use the Steam version of the game because the official website only gives you the latest version, or even not being able to use the latest (paid !) expansion pack.)

[u/Pale_Ad9494 → u/SunsetHippo]

I’m getting downvoted to oblivion so there’s at least a bunch of people that disagree. But what are you doing in game if nothing is happening for hours? I’m probably biased the other way since I play almost exclusively in multiplayer with friends but I would never say there isn’t enough to do while playing.

[u/SunsetHippo → u/Pale_Ad9494]

between waiting for events, research, or just not really having an objective at the moment, you can just sit there. .waiting, enjoying the ambience. which over a colony's lifespan can build up.

[u/Pale_Ad9494 → u/SunsetHippo]

All performance gains are great but I think given a built in multiplayer or the ability to run 1000 mods, the average person would be more likely to explore playing the game with friends over implementing that many mods. Plenty of people play the game and never end up in pcmr.

[u/JaesopPop → u/Pale_Ad9494]

I don't think the average player cares about multiplayer. They do care about performance, and this impacts basically everyone who gets to a late stage colony.

[u/BlueTemplar85 → u/JaesopPop]

Like in other games, the average player stops playing the game before they ever get to a late stage colony.

[u/JaesopPop → u/BlueTemplar85]

Plenty of folks get to a large enough colony where they will see a notable impact from this update. Certainly more than people wanting an official multiplayer mode.

[u/BlueTemplar85 → u/JaesopPop]

Where does this certainty comes from ? We don't know how many potential players never gave it a shot because the game doesn't mention multiplayer.

[u/JaesopPop → u/BlueTemplar85]

Where does this certainty comes from ?

My time engaging with the RimWorld community, who notably are overwhelmingly thrilled with this update and have not wished it was something else instead.

[u/BlueTemplar85 → u/JaesopPop]

Why would you think that the "Rimworld community" (by which I presume Rimworld redditors, or even worse, Rimworld streamers ?), is representative of Rimworld players ?

[u/JaesopPop → u/BlueTemplar85]

Why would you think that the "Rimworld community" is representative of Rimworld players ?

...yeah, I can't help you man. I'd be happy to hear your basis for declaring that people were simply clamoring for an official multiplayer mode.

[u/GlorifiedBurito → u/Pale_Ad9494]

No, it wouldn’t

[u/Quinnlos → u/Pale_Ad9494]

When most of the playerbase is running hundreds of mods that are slowing their games down you would be wrong.

You’re also not taking into account the actual late game and having fucktons of entities being processed.

[u/BlueTemplar85 → u/Quinnlos]

If you redefine 'playerbase' to exclude the low engagement majority of players, sure.  

Also, the playerbase would be different if official multiplayer had existed for years.

[u/Pale_Ad9494 → u/BlueTemplar85]

Both points are correct I think. “Most” of the player base isn’t on pcmr commenting on the game and multiplayer as a feature attracts a broader base as well.

[u/roguebananah → u/Pale_Ad9494]

Staying away from multiplayer is why Rimworld is fantastic. The best gaming decision I’ve ever made is stop playing multiplayer

[u/RiffyDivine2 → u/Pale_Ad9494]

As someone who wants multiplayer, fuck no. This improvement is massive and the multiplayer mods will benefit from it.