Check out “SimCity Four” on YouTube, and likewise you’ll behold gamers constructing multilevel twin carriageway interchanges and advanced railroad networks, or possibly even a swooping flyby of a sprawling metropolis. None of these parts got here with the usual sport, which used to be launched correct after the flip of the millennium. They’ve been developed slowly and painstakingly over the 22 years since its commence by dedicated aficionados — a thriving crew that continues to push the game’s limits.
The work is a labor of esteem, and it’s a quantity of labor and esteem. Modder Tarkus says that as a minimal these years, he’s drawn to the deep and advanced nature of the game’s simulation, which he says remains unmatched by more contemporary video games admire Cities: Skylines (2015) and its sequel Cities: Skylines 2 (2023) — and even by SimCity Four’s have faith sequel, which used to be launched in 2013 and merely known as SimCity. Modder Ulisse Wolf says that, for him, it’s in a roundabout way a inquire of crew. Perchance thanks to the game’s age, he finds that SimCity Four enthusiasts are “extra broken-down … guaranteeing you a peaceful design to stay in [peace] with varied contributors.”
SimCity Four used to be launched in 2003, the fourth in sport company Maxis’ series of metropolis-building video games. It used to be reasonably winning, garnering definite opinions and promoting smartly adequate for Maxis to commence a selection pack later that year. The flexibility for gamers so as to add their have faith express material to the game used to be a key section of SimCity Four’s appeal from the originate: it got here with a location of instruments that allowed gamers to invent and add their have faith structures to their cities. Players rapidly began sharing their creations on-line by way of exchanges hosted on fan websites admire Simtropolis and SC4 Devotion (now defunct, nonetheless relaunched only lately as SC4 Evermore), as smartly as discussing pointers and ideas within the accompanying boards.
“It grew to alter into clear to me that if I wanted to behold extra occur on the transportation modding front, I needed to discover discover how to attain things for myself.”
Players rapidly began to request beyond the formally supported strategies of including their have faith express material to the game and wondering what else could be performed. Could possibly well the game’s road draw be expanded? What about the railways? Early modding efforts were made more straightforward by the style the game stores its records, which, as modder Matias93 explains, is in a database whose format used to be shared with outdated Maxis video games. The database stores records about the game’s varied aspects: for a construct of road, the database would comprise entries for all the things from which textures to expose on masks masks when the player placed the road all the style down to how noteworthy site site visitors the simulation would enable it to elevate.
The sport’s built-in instruments supplied no manner to access this database, so the crew developed its have faith — no easy job, as Matias93 explains: “[This] required the reach of a veritable suite of instruments in a position to decrypt hexadecimal symbols into legible databases, and to import and export multimedia facts from and to them.”
As early modders began to salvage their manner around the database, nonetheless, they began to salvage entries for methods that weren’t within the game: parts that were either unfinished or never applied. “SimCity Four presentations clear signs of getting gotten much less express material and expansions than its creators [intended]. While a quantity of these aspects are nearly irremediably broken … many others were comparatively at reach to be repurposed,” Matias93 says.
The usage of the instruments they’d developed to tweak existing entries, modders were in a position to create the rudiments of these unfinished parts into totally contemporary ones. One in every of the first such parts to be repurposed used to be an unused road kind, it appears supposed to be a dirt road for use in rural environments. SimCity Four comes with loads of kinds of roads for gamers to design in their cities: suburban streets, two-lane roads, two-lane one-manner roads, four-lane avenues, and highways. Players rapidly chafed against the barriers of the latter: there used to be no manner to create a twin carriageway with loads of lane widths, and connecting a twin carriageway to a road community required utilizing one in all loads of prebuilt interchanges. Players who wanted to make and create their have faith interchanges, or construct highways with loads of widths, were out of luck.
The discovery of the unused dirt road meant that there used to be plight for one extra road kind, and modders venerable it as the foundation for what grew to alter into the “proper twin carriageway” mod, a extra versatile and customizable different to the game’s built-in twin carriageway draw. , gamers had a few twin carriageway widths to derive from, as smartly as modular pieces they’d per chance use to create their have faith personalized interchanges.
Tarkus recollects coming across an early model of the mod in 2006: “I was fully floored. [Even though] it used to be an especially restricted mod at the time, I would teach it had seemingly.” True-existence commitments took him a long way from the game for most of that year, and on his return, he came across that construction had stalled. “It grew to alter into clear to me that if I wanted to behold extra occur on the transportation modding front, I needed to discover discover how to attain things for myself.”
As of late, Tarkus is the lead developer on the Network Addon Mod (NAM), a sprawling kit that entails the RHW mod alongside with an mammoth quantity of varied transport-essentially based express material: pedestrian retailers, a brand contemporary railway draw, roundabouts, canals, bridges, and underpasses, as smartly as a comprehensive transforming of the game’s site site visitors simulator. The mod remains in active construction — its 49th model used to be launched in March 2025 — and is maintained and developed by a for all time sharp and evolving team, whose membership spans the globe.
Lucario Boricua, who spearheads construction on loads of of the mod’s parts, lives in Puerto Rico and is a civil engineer by day. He estimates that, as of early 2025, the team has around 25 plump-fledged contributors, alongside with varied section-time contributors, playtesters, and many others. The crew is enough in unheard of, too — contributors salvage in each the long-working boards and more contemporary channels admire Discord, and each are on the total positive areas to spend time, with feeble contributors welcoming contemporary fans and what Wolf calls “political bullshit” particularly absent.
It’s no longer correct the NAM that continues to be in active construction, either. In 2025, SimCity Four modding continues to evolve and embody contemporary chances, largely thanks to improved access to the game’s supply code. Matias93 explains that “the first 15 years of modding, roughly, [had nothing] to attain with coding per se.” As an different, they alive to customizing and extending the game’s databases. Nonetheless, that modified within the 2010s thanks to 2 key dispositions.
The main used to be the commence of half of the game’s code, supplied by the gradual Paul Pedriana — the game’s usual chief programmer — in response to a quiz from the crew. This allowed for the reimplementation of among the game’s inner debugging parts, which comprise been the truth is cheat codes that allowed developers to attain things admire rapidly location up cities with out caring about practicalities admire having adequate in-sport money, design particular structures straight away, and many varied smartly-behaved parts. Then, in 2019, a sixty four-bit macOS port of the game used to be launched — with an surprising bonus for modders. “Many of the game code [was] legible on the launched executable, permitting modders to title obvious which you may possibly well judge hooks to work with,” Matias93 says.
Modders proceed to lack plump access to the game’s code, nonetheless even restricted access has allowed utilizing tactics that could per chance per chance comprise otherwise been no longer seemingly. Foremost amongst these is utilizing dynamic hyperlink libraries (DLLs), which allow personalized code to be loaded into the game’s executable at runtime. The flexibility to jot down personalized DLLs has allowed modders to repair long-standing bugs within the game — most particularly, one notorious subject that could per chance end result in assign sport corruption in substantial cities. It moreover let them dream up parts that should always nonetheless no longer comprise been which you may possibly well judge otherwise: newest additions consist of a 3D camera, the reimplementation of the game’s long-broken water draw, and a Steam Workshop-esque interface for locating and downloading personalized express material.
On the opposite hand, the technique of putting in these parts remains a long way much less easy than for contemporary video games, which assuredly reach with dedicated construction kits designed for modders’ use. So what is it that keeps the NAM team and its fellow modders engaged on SimCity Four, painstakingly imposing contemporary parts and testing the limits of what’s which you may possibly well judge?
Lucario Boricua says that engaged on the game nowadays feels admire “standing on the shoulders of giants.” The a long time of labor that modders comprise build into the game provide a platform for nowadays’s creators to push the game into areas its designers potentially never imagined: “We’re desirous about doing modern things that redefine what’s which you may possibly well judge.”