City-Builders in Motion

I have always loved games where you can build and simulate theme parks, hospitals, cities and even empires. There is something wholesomely enjoyable about crafting an environment that leads to maximum happiness for as many of your citizens/customers as possible. Unless you’re playing “Afterlife” or “Hell Architect”. The happiness there is mostly yours and yours alone.

Since the first “SimCity” in 19891, city-building games (CBGs) have come in two flavours. One provides an ever increasing level of realism, as do “SimCity” and “Cities XL”, for instance. In contrast there are games such as “The Settlers” or “Tropico” where the basic concepts of the simulated entity are simplified, sometimes to a cartoony degree. Both flavours are still going strong with entries such as “Cities: Skylines”, “Timberborn” and “Frostpunk” promising an increasing variety of genre expansion and genre cross-pollination.

What has always bugged me about the CBG (sub-)genre, however, is that these games have privileged the role, size and prevalence of residential buildings over that of public, ceremonial, palatial or monumental buildings. You might plop down a thousand houses in a game like “Pharaoh”, but your Mayor’s Mansion or Pharaoh’s Palace are single buildings usually no bigger than two or four regular houses respectively. And this trope of the sub-genre is endemic and in no way limited to only one of the two flavours available to us. Town halls, palaces, administrative centres, all of these are single-purpose and insular buildings, while residential buildings throng around them willy-nilly. In some cases, it is commonplace to put your administrative/town centre away from the actual centre of your town. Yet, such structures have always been multi-purpose throughout history and they have never ceased to be central to public life. A critical synergy between these two entities is lacking in CBGs. Clearly, something must be done! Endeavouring to change this, I had an idea…

Backing up before we move forward

First, however, I should probably list the key features of what makes a city-building game and some notable examples. The easiest way to do that is to give you a small overview of the simulation genre itself because CBGs fall under the heading of simulators, simulations or simulation games2. This category includes games such as “Microsoft Flight Simulator”, “Farmville”, “Tony Hawk’s Pro Skater”, “Sid Meier’s Civilization”, “Spore” and everything in between.

We can subdivide these games by their main mechanics or systems, and depending on the complexity of the game, some of these types can be added together to create sub-genres such as city-building games and tycoon games. In general, simulation games take a real-life skill, activity, process or problem and try to simulate them digitally. No matter how scaled down or simplified the simulation is, what makes it fun is playing around with aspects of real life in a secure environment, and challenging your problem-solving skills3. In that sense, simulators are no different from other games. They are meant to be fun. But rather than testing your hand-eye coordination or your strategic acumen, these games challenge your ability to plan ahead and think about systems on a higher, more abstract level.

Types of simulation4

  • Resource managers: games where you mine or receive resources, and create and maintain production lines and supply chains to manufacture finished products.
    e.g. “Satisfactory”, “Dyson Sphere Program”…
  • Trade managers: games where you have to create efficient road networks, trade routes, or transport infrastructure to facilitate traffic, trade or mass transit.
    e.g. “Euro Truck Simulator 2”, “The Guild”, “Transport Tycoon Deluxe”…
OpenTTD: an example of a trade manager and a tycoon game.
A cargo distribution centre in “Open Transport Tycoon Deluxe” (OpenTTD). Cargo is being moved between the different modalities shown: airplane, train and truck.
Source: OpenTTD website
  • Person managers: games where you have to fulfill the individual needs of persons, creatures and/or buildings, whereby they can either level up or upgrade. Or games that simulate the individual behaviour of crowds of non-player characters.
    e.g. “The Sims”, “Spore”, “Ultimate Epic Battle Simulator”, “Democracy 3″…
  • Builders (or space managers): games where your main objective is to create something functional, or to maintain it, mainly by placing down buildings, machines or objects.5
    e.g. “Reus”, “Islanders”, “Utopia”, “Townscaper”, “From Dust”…
Reus: an example of a space manager.
The four giants (or reuzen) that you use to mold the planet. In the case of “Reus”, you put down environmental zones, such as forests, and plains oceans, mountains and swamps. You also put down minerals, plants and animals to develop villages like this one.
  • Profession managers: games where you as the player take up the burden of a craftsman, employee or athlete, sometimes from a first-person viewpoint. This type of games blurs easily with sports games. If a line can be drawn between the two, it is that “real” sports games focus on the physicality and competitive nature of performing the sport (e.g. Wii Sports, where you can golf or play tennis with the controller), rather than (merely) simulating the conditions in which a sport takes place.
    e.g. “PC Building Simulator”, “Shenzhen I/O”, “Tech Support: Error Unknown”, “Cooking Simulator”, “Microsoft Flight Simulator”, “Drug Dealer Simulator”, “Goat Simulator”…

Sub-genres of the simulator game genre:

  • Tycoons: games where you run a business, which involves combining two of the four basic mechanics, and sometimes three. Usually profession, trade or space management.
    e.g. “Railroad Tycoon”, “Two Point Hospital”, “Project Hospital”, “Tavern Master”, “Crossroads Inn”, “Planet Zoo”, “Jurassic World Evolution”, “Project Highrise”, “Theme Park”, “Planet Coaster”…
Project Hospital, an example of a realistic tycoon game.
A patient is collapsing: a common occurrence in “Project Hospital”. In this game you build and manage a hospital and you support its staff. You can let them take care of the patients, or step in yourself to crack the hard cases. Maybe it’s Lupus?
  • City managers or base builders: games where you create and maintain a city or base, tending to the needs of your inhabitants, which involves combining two of the four basic mechanics, and sometimes three when there is an overworld map that allows you to use your city or base as a staging area for conquest. They usually involve space, resource and – sometimes – person management. They also borrow some mechanics from the real-time strategy game genre, such as combat and defensive/offensive structures and units.
    e.g. “Hammerting”, “Dwarf Fortress”, “RimWorld”, “Age of Empires”, “Maia”, “Moonbase”…
  • At its heart, CBGs are urban planning and economy management games where you plan and lay out or construct your settlement by hand. The needs of your citizens are an important factor in deciding your success, and you are induced to earn money by gathering, processing and trading resources. Usually CBGs combine three of the four basic mechanics: building, resource management and economy management; sometimes, person management is also included.
    e.g. “Caesar”, “Pharaoh”, “Tropico”, “Anno 2205”, “Banished”, “Ancient Cities”, “Grand Ages: Rome”, “Nebuchadnezzar”, “SimCity”, “Cities in Motion”…
  • Empire managers or Grand Strategy games: these games incorporate everything the simulation genre can throw at them, and then some. They are not afraid to incorporate aspects of real-time strategy games or of role-playing games.
    e.g. “Crusader Kings”, “Europa Universalis”, “Grand Ages: Medieval”, “Jon Shafer’s At the Gates”…
  • 4X-games: these are games where you explore the map, exploit resources, expand your territory, and exterminate your enemies. They are strictly speaking not a part of the simulation genre, but depending on which X they lean into, they can be considered a cross-over from real-time strategy games into simulation games. Obviously, the more a game tries to do, the more boxes it ticks, and the more genres it entangles itself with. The difference between a 4X and Grand Strategy game is murky. Generally, I consider games that allow you to pause to be Grand Strategy games, whereas 4X games are turn-based in nature, but you can judge by the examples I give that this qualification does not always hold true (cf. “Jon Shafer’s At the Gates” as an example of a Grand Strategy game).
    e.g. “Sid Meier’s Civilization”, “Master of Orion”, “Shogun: Total War”, “Stellaris”…

Apart from these sub-genres, there are probably many others you could invent based on how you cobble together the basic features of simulators and tie in features from other genres. Tower defense games, for instance, are base-builder games, but very few of those games lean into the realism of a city under siege. Similarly, a game like “Frostpunk” is a CBG, but the added element of a choice-based tech tree and the emphasis on survival in the face of ever-growing odds has given a much needed twist to the old formula.

You could also split up each of these sub-genres further depending on their historical setting, be it ancient, medieval6, fantastical, contemporary or futuristic. Besides that, ever more twists are being introduced to these kinds of games by means of mixing and matching different genre features7.

Organic building development and agglutinating housing

Back to my gripe: the synergy between public buildings and residential buildings or neighbourhoods is severely lacking in most CBGs. Houses, for the longest time in history, were places where you rested your head, stored your valuables or performed work that you couldn’t, wouldn’t or shouldn’t do if there was a risk of rain. Most activities were performed outside, even in countries where the weather was frequently inclement. Houses were high maintenance buildings. They would wear down quickly since they were often made from wattle and daub, or wood and straw, or other natural products easily at hand, so limiting the size of your house was a perk. Only the very wealthy could afford to use stone or planks made of dried wood, which would last you a lot longer. And if it was cold during the winter, the smaller the space that you needed to heat, the better for the peasant who has to chop his own firewood. Yet, in CBGs, houses are quite big in contrast to public spaces, and they usually only allow for habitation, not for cottage industry manufacture – which up until the industrial revolution was the standard means of production.

On the other hand, there is a lack of public spaces and buildings in CBGs. Most games separate out the functions of such buildings: a square that allows traffic by foot or cart, a courthouse, a treasury, a marketplace, a tax collector’s office, a temple, an administrative centre, a public forum… These would all be separate entities in most games. Yet, the Forum Romanum provided all of these functions, and though it was composed of both roads and buildings, many of those roads and buildings doubled up on functions. Roads could provide room for stalls and hawkers one day and would be swept clean to provide space for an audience listening to a politician speak another day, or the main thoroughfare would be kept free when a triumphal procession would march through on its way to the Capitoline Hill. No CBG has as yet been able to field such multi-functional buildings, never mind that they are the rule in real life and not the exception. Of course, this might have been due to technical limitations or the limited scope of the game project, but CBG scoming out now are falling in the same trap.

Image: By Pieter Bruegel the Elder – 2. Kunsthistorisches Museum Wien, Bilddatenbank.1. The Yorck Project (2002) 10.000 Meisterwerke der Malerei (DVD-ROM), distributed by DIRECTMEDIA Publishing GmbH/Public domain
This is a painting by Pieter Brueghel the Elder and, honestly, I haven’t a clue as to what’s going on. Here and there you can see craftsmen going about their work. Mostly, however, it is clear that this medieval Flemish town square was a hopping place buzzing with various activities, with people working, carousing, haggling and observing.

In a genre that esteems realism, these are glaring oversights. In the following sections I will mostly be giving examples of how my solution would work in terms of a CBG situated in the Roman period8. Don’t worry, I see no reason why you could not implement this design in other city-builders situated in other time periods. I will go into that a bit more towards the end.

In a nutshell, what I would like to see are public buildings that have large up-front costs and occupy large spaces on the map. They upgrade as your city grows, providing more services and generating a sphere of positive prestige effects to residential areas around them. Residential buildings would gradually agglomerate into residential areas and as they grow, unlock the ability to act as manufacturing hubs. Of course, cities are composed of more than residential and public buildings, so let’s take a look at how they can fit in with other types of buildings.

Buildings that play together, stay together

I propose that, in the main, there are only five types of buildings or objects that you can place in any CBG. They are defined by how they interact with the other building types. Note, this is an abstract classification and thus need not dictate how the user interface looks like in any CBG.

  • Public buildings & monuments: this category includes utilities such as aqueducts or water pipes and harbours or train stations. It might be a bit of a misnomer considering how in contemporary games you might argue that certain utility companies are privately owned (or have been privatized at some point). Other buildings such as a town square, forum, palace, agora, souk, temple complex, pyramid or ziggurat also fall under this heading and behave as large, usually centrally located structures that upgrade as the game progresses. They affect neighbouring residential areas, positively or negatively.
  • Residences or residential areas: agglomerations of individually placed houses which can generate half-finished and finished goods. They are positively or negatively affected by nearby buildings, other neighbourhoods or topographical features, which will stimulate or stymy their growth and development.
  • Primary resource gatherers: industrial or commercial buildings that generate primary resources, often to be placed close to those resources, such as ore mines, woodcutters, charcoal burners, dye-works, tanneries etc. This also includes farming and husbandry.9
    Commercial buildings such as offices, parking garages, restaurants, dance halls etc. will also fall under this category. These are buildings that are of a moderate size, that (mostly) do not require any input resources except for labour, and that may serve a public function, but that have historically been privately owned. In a sense, this category is for “other” buildings that do not fit the mold of any of the other types, or that only fit the old mold where the ratio of building placement versus functionality is one on one.
  • Roads: there are two kinds: publicly maintained roads, which are the kinds of roads used in most CBGs, and alleys, which would spring up whenever two buildings or neighbourhoods are sufficiently close to one another, but don’t agglomerate (as in the case of residential buildings).
  • Beautification: all manner of gardens, objects and structures that can be placed throughout the city (except on roads) to improve the land value or prestige of public buildings and residential areas. Also decorative objects or buildings.

I will be going into the specifics of each of these types in the next sections.

Public buildings and residential districts

Imagine you are building the city of Rome. The Forum Romanum would be one of your earliest structures, but it starts out as an empty field with a wooden podium. This field would be huge! it might still be partially flooded or include part of a hillside without clipping into the terrain. Over time, as your city grows and as you complete missions or objectives or assignments or fulfill criteria, the forum would become more prestigious-looking, with smaller buildings popping up inside of its bounds, and it would gain certain functionalities, such as acting as a marketplace and a warehouse, being a service building for jurisprudential, administrative and religious matters etc. At times, you might have to invest resources into upgrades for the public building, to turn brick into marble, for instance. You might even be able to choose which services the Forum will provide and deactivate previous choices. Nearby residential areas would get a boost from being close to any such building that leveled up.

At first, these public buildings (or building sites) might even negatively affect residential areas surrounding them. The CBG “Grand Ages: Rome” does a (very limited) version of this. The Forum you build does improve in looks, but it does not impart prestige and has no real functionality. In fact, in “Grand Ages: Rome”, you are often better off throwing the Forum down somewhere out of the way, because it impedes the synergy between workshops and houses, who need to be in range of one another. Having a large, pointless building smack dab in the middle of your city… Why bother, right? Sadly, you do need it to unlock other buildings in the early stages of developing a city. It was a poor execution of a good idea.

Grand Ages: Rome, the Forum building.
The Forum building in “Grand Ages: Rome”, which is markedly larger than all other buildings. In the top right you can see the challenges (or accomplishments) that will unlock columns, a triumphal arch, garlands etc. Beyond that, the Forum is a drain on your resources.

“Nebuchadnezzar” is a recent CBG that incorporates the novelty of building customizable temples/ziggurats. Instead of having public buildings grow organically based on the kinds of criteria that are met, you could build them yourself. New parts would be unlocked or researched that you could then add to the public building site however you wished. In “Nebuchadnezzar” there are also templates. You would not have to worry about making the building pretty yourself and you could let it grow on its own into a predetermined shape. While the mechanic I propose is slightly more radical, I personally would be happy simply seeing this concept gaining wider acceptance.

Other kinds of public buildings could only benefit from becoming more multi-functional:

  • an emporium = granaries + warehouses + (slave) markets;
  • a gymnasium = baths + athletics field + food stalls;
  • a sports complex = athletics field + horse race track + fight ring + swimming pool + food stalls;
  • a temple complex = temple + brothel (depending on the setting) + gathering place + astronomy laboratory + treasury;
  • a palace = seat of government + treasury + tax collector’s office + residence of the governor/emperor…

Keep in mind the effects of the services they provide, as well as the prestige they might generate for their neighbourhood, and how leveling them up might even synergize with other systems in the game. The player could unlock buildings, units or technologies by having a sufficiently developed public building. Depending on the services the player chooses to unlock, they could improve overall research or provide access to inter-city trade or gain trade routes on the world map, or provide (an increasing number of) workplaces for different classes of citizens… The options for added features are not quite endless, but the possibilities for combining them are, and that is what will be important for developing public buildings this way in different historical settings.

This is “Nebuchadnezzar”. The large structure in the centre shows a temple being built. Below you can see that there are two temples you can build: a custom version and a pre-built version. Also check out the screenshots on the Steam page for finished versions.

Every such large or monumental structure would be an ongoing project to invest in with milestones and modifications. Some could be unmodified and invisible, such as the the Cloaca Maxima, but investing in such projects might enable the creation of aqueducts or fountains, grant your citizens fresh water access, or improve the overall health and prosperity of your population. Other large construction projects that have sustained cities historically, are dams, embankments or floodplains to curb river flooding; sewer systems, catacombs, cemeteries, military drilling fields (e.g. the Campus Martius), subway systems, ring roads, train stations, mass transit, large tunnels or bridges. “Anno 2205” inches into this notion by having you invest in large projects (bridges in this case) to unlock additional parts of its maps.

As mentioned before, you would still need to create farms (a resource gathering building), but granaries, docks and marketplaces would be incorporated in public buildings (or they would themselves be a large public building, such as the Souk, the Emporium, a supermarket, a mall etc.). In Roman cities, forums, bath houses, insulae, even temples or temple complexes and large entertainment buildings like the Hippodrome or Colosseum all featured commerce in some form or another, either built in – like the stalls in the peristyles of large gymnasia – or on the outside, like the shops built up against the walls of churches in medieval Europe. Depending on their level, public buildings could distribute several types of goods which would benefit nearby neighbourhoods.

Speaking of residential areas: in medieval cities, certain streets were called by the profession of its inhabitants/store owners: butchers, bakers, coopers, candlemakers, ropers, blacksmiths, whitesmiths, tinsmiths, armorsmiths, engravers, book sellers, carpenters, bankers, minters, artisans etc. Many of those street names still survive to this day.

How could we translate this to the mechanics of a CBG? A grouping of houses would level up to become agglomerated into an insula or neighbourhood or slum. These agglomerations can vary in shape, size and look, growing organically with every new house added to it. Once a residential area grows large enough, it can be assigned the generation of goods. While there would still be a separate building for, say, a woodcutter, a clay pit, or a stone quarry; artisans such as furniture makers, potters and sculptors would work from home. For pottery I refer you to the Kerameikos: a neighbourhood in Ancient Athens where they specialized in the creation of pottery. Its products were so famed throughout the Mediterranean in ancient times that the superordinate word for all types of pottery is eponymous from the district: ceramics.

Depending on your policies, your traits (as a mayor, governor, king, pharaoh, Caesar, tsar…), your population level and the development of nearby monumental buildings, your residential areas would produce more goods of higher quality. You could sell or exchange these goods at trade markets (or public buildings which feature this function), and depending on the quality, your citizens could strike better deals. Residential areas would need to gain access to their raw materials, either by being in range of the gatherer or of a warehouse storing the resource. (That in itself is not new to the CBG genre.)  Commodities can be put in different groups such as “foodstuffs”, “semi-finished goods”, “luxury goods” etc. for those who want to keep things simple, however, this is not a requirement.

As housing blocks level up further and increase in size, they might even be able to take on crafting a second commodity. If you do classify commodities, doubling down on the same type of commodity might either grant a permanent benefit to both commodities, or kick-start the quality level of the second commodity, allowing it to level up in quality faster. There will likely be other ways in which residential areas might synergize with themselves, with neighbouring areas, or with public buildings. I cannot predict whether those synergies would be useful for balancing out the gameplay, but this design is versatile enough that some use could be made of these options.

Pharaoh: Cleopatra
Red roadblocks restrict the city service walkers, such as the fire station porter on the bottom left or the market saleswoman dressed in green bottom right. Not only are the roadblocks in “Pharaoh: Cleopatra” ugly, they lead to blocky cities.

It pays off to build several neighbourhoods that are non-continuous, spread out around public buildings. Those neighbourhoods that require wheat to (create flour, which they would deliver to neighbourhoods which) create bread would also be able to have access to the goods they generate (i.e. flour/bread). Having several neighbourhoods close together would allow you to easily exchange goods between neighbourhoods, serving to help upgrade all of them in tandem. Obviously, once the needs of your residents grow to the point where you need to build residential areas outside of this core cluster, you will have to start balancing out the exchange of goods via public buildings. The CBGs developed by Impressions Games (e.g. “Caesar”, “Pharaoh”, “Zeus”, “Emperor”…) work in the opposite way. These games introduced the notion of “walkers”, NPCs sent out by bazaars or markets which would follow the road and deliver goods to houses they passed, as long as said goods were stored in the market and required by the domicile. Though I love these games for their depth and charm, the walker mechanic has always bothered me. It is an elegant way to circumvent simulating every citizen separately or to bypass food distribution by level of wealth, but it is a reduction of complexity that we can now afford to let go of.

Roads and agent-based need fulfillment

As stated, residential areas would obviously have access to the goods they themselves manufacture, but what about other residential areas? How do they gain access to the bread made in Neighbourhood A? Most likely, they will have to acquire their bread from a nearby neighbourhood, from a marketplace or from a public building that allows for the storage and distribution of bread. And if the market does not send out an NPC to deliver bread, then every citizen will have to fend for themselves. All citizens will be free agents.

Such agent-driven systems10 have been introduced in games before: “Immortal Cities: Children of the Nile”, “CivCity Rome”, “Dawn of Man”, “Frostpunk” and “Dwarf Fortress”, and even in earlier games such as “Knights & Merchants: The Peasant Rebellion” or “Alien Nations”, where NPCs were limited agents who grew hungry and would repast at an inn or town hall, interrupting their activity for a short time. I really like this dynamic, even though the AI might not always play nicely with the pathing or have a good sense of timing.

An example of an agent-driven system is on display in “Dawn of Man” where hunters might have to track prey a ways away from the main settlement. It might happen that these hunters turn back at some point because they are hungry or thirsty, even though they are likely passing small streams, berry-laden bushes and fruit-bearing trees all the time. Worse still, these hunters turn back too late, at the cusp of dehydration or starvation, instead of having calculated how long it would take them to gather food or drink before they are to die. So, if you are going to use an agent-driven system, the intelligence of any single agent will have to be greater than that of your average rock.

Knights & Merchants: The Peasant's Rebellion
This is “Knights & Merchants: A Peasant Rebellion”. In the Inn, here centered, your serfs and craftsmen gather to eat when they are hungry. As you can see, they are out of sausages. Only six men can be served at the same time, but each unit has an individual timer, so you can spread out their lunch break. When an inn is extremely busy, the entrance of the Inn can be swamped with people trying to get in, people trying to get out, and serfs trying to provision the inn.

Our imaginary Rome now has citizens living in neighbourhoods who have to go pick up bread, and water or wine or beer, and clothes or furniture or olive oil, and pottery or glass or fine goods etc. They might also have to visit a doctor, or a temple, or a prostitute, or a lawyer and so on and so forth. These citizens will have to spend part of their time getting all of that done, and work besides. In “CivCity Rome” households were composed of a wife, a husband and slaves. The husband would go to work and pick up stuff for the household in his spare time. The wife would be busy non-stop making sure that the house was stocked with all the necessities; once the family was wealthy enough, she would also acquire slaves, and they could be sent out to do part of the work for her; after all, with every upgrade of the house, the family would require more goods and services. This system worked really well, though I’m not proposing we keep a similar (and sexist) model, true or not.11 After all, a game like “Banished” shows that bachelors and bachelorettes can take care of themselves just as well.

No matter how you get agent-driven citizens to work, you have to visualize their range for the player upon placing a house, and you have to determine path-finding from one position to the next for every agent. This agent-walker distance or the radius people are willing or able to walk from their domicile is twofold: one zone shows the certainty of a citizen being able to get that good or service in the course of their day, and the other is for determining the possibility of a citizen having access to a commodity or service, depending on the workload of your citizens and how far they have to travel to and from their domicile or place of work. Housing districts would be porous, meaning that residents can walk through them without hindrance. Adjacent neighbourhoods would thus not impede each other’s service area. Public buildings on the other hand might impede a walker, because passage might be restricted. A palace, granary, warehouse, wharf, casino, or factory might require walkers to go around, thereby decreasing the radius of a neighbourhood’s area(s) “behind” such a building. Instead of two concentric circles, you would get irregular concentric ovoids or dented circles.

CivCity: Rome
This small insula in “CivCity: Rome” is occupied by a man, his wife and their son. As you select a house, arrows point to where the inhabitants are in the city. By the symbol of praying hands you can tell that the man has gone to worship at a temple while the wife just got home shopping for groceries, and the boy has yet to attend his lessons at the Grammaticus.

For example, citizen A works in a salt mine outside of town. They will have less time to gather the resources they need to improve their standard of living. They are technically poor, and will remain so until they get a job closer to home, especially because they can only get better clothes on the other side of the river, but there is no bridge close to them. Citizen B is a potter and can work from home. Depending on how far he has to walk to get his clay – which may be lying in a warehouse just around the corner -, he will have far more time to tend to his daily needs and over time will become more affluent. At this point, we haven’t even actively simulated a cashflow economy on the level of individual agents (which you can do), but we can already see a divide between classes: the labourer and the craftsman. We could simulate such an economy by determining housing block growth based on the kind of commodity manufactured there, and its quality. That still doesn’t quite get us to a differentiation between proles, plebeians, craftsmen and merchants on the one hand, and equites and nobilitas on the other hand, however. Is this necessary? Maybe; maybe not. It will depend upon the kind of game you want to make. The current system would not impede such a development or added system. Regardless, it is not something I will dwell on further12.

These agents will require some way to travel across the map to get to the shops or markets. Mostly, they will be using roads. Roads are usually faster than travelling across forested, broken or fallow ground, after all, especially if the agent is using a hand-cart or wheelbarrow. They are especially useful in comparison to walking through walls.

I make a distinction between roads (or thoroughfares, or railroad tracks, and other forms of transportation such as maglevs, hyperloops, warp-lanes etc.) and alleys. Alleys crop up wherever two adjacent houses or housing blocks are not linked – though they might have sky-bridges in modern or futuristic settings – or are specifically zoned to prevent them from agglutinating into one whole. Roads are official junctions that allow for (more than pedestrian) traffic: the passage of horse and cart, of cars, or in the case of canals, boats and gondolas. Larger roads could facilitate parades, processions and triumphal marches etc. While alleys are not explicitly maintained nor require much upkeep, roads are maintained with public money. A widening or crossing of a road can generate a square or piazza. This may be a form of beautification, depending on the surrounding neighbourhoods/buildings. It would stand to reason that roads provide faster traversal than alleys. Mostly, alleys are there to serve as a visualization of how a city in general – and a residential area in particular – is a porous thing. Alleys would also pop up between residential districts and other types of buildings that are placed close to them, such as primary resource gatherers or public buildings.

Beautification and putting it all together

Beautification as a “type of building” is slightly misleading. First, all (types of) buildings could/will have positive and negative prestige effects on surrounding buildings. Second, while beautification buildings will generally always provide positive effects, they might, thirdly, merely be inert objects that provide visual splendour and do not detract from or add to a region’s desirability or land value. They might also provide space to separate undesirable buildings from a residential area. Small elements of beautification would be an integral part of the organically growing public buildings and residential areas to showcase their improved appeal visually. Homes could feature (roof) gardens, terraces or balconies. There might be an indication of atriums with trees in them, or small squares (of alleys) inside a residential area, some with fountains or statues. You can also go the opposite direction: adding beautification to existing public buildings and residential buildings (i.e. putting down a building or object inside another building or building site) would change their look and improve their appeal. Thus beautification is a combination of functionality and personalization.

If you can build beautifying elements inside other buildings, or build houses close enough together that they agglutinate, or just far enough apart that they don’t, then how do you determine a building’s dimensions for pathing, for auto-snapping and for agglutinating? What if the building is triangular, square, round, oblong, irregular or octagonal etc.? Many games have solved this problem by making a building’s base rectangular, adding empty space to fill out the irregular shape. “Cities: Skylines”, though it allows for free-form road building, makes the player adhere to the box-grid when it comes to buildings. They all have a square or rectangular base.  Cities: Skylines’ free-form road building tool is very similar to how road-building works in “Black & White 2”, where towns naturally look more curlicued and organic as a result. In the case of “Black & White 2”, which is a CBG inside of a God Game, buildings and roads are not placed on box-grids. Instead they snap to the roads that you lay down where the terrain allows for it.

Black & White 2
Thanks to the flexible road building in “Black & White 2”, you can create a sprawling city with curvy roads. Every building, column or street lamp functions only when snapped to a road.
Source: Magxardas on Deviantart

This road-snapping is a pretty neat thing, but how about making it work the other way around? Instead of buildings snapping to roads, we snap roads to buildings. And how about both? You can build a road in a free-form and then snap buildings to it, or you can lay out (a district of) buildings, and then drag a road around or next to them. It’ll snap to the outer bounds, and alleys will form, branching off the road. With a single key – such as Shift or Ctrl on Windows and Cmd on Mac – you can toggle to stop the game from snapping roads or houses to (other) roads or (other) buildings. You might also drag a road next to a residential area without having it snap. If it’s close enough, the residential area will gradually grow outwards until it encounters the road. In the case of public buildings and primary resources gatherers, having rectangular placement boxes for buildings is a simple solution, but for the purpose of road snapping, maybe the “empty space” that is included in the building’s blueprint could be fuzzy. By that I mean that the road snapping to such buildings would abut to the structure, and not merely the empty zone around it. This would allow for more irregular shapes inside of the placement boxes while also maintaining an organic look where buildings don’t look divorced from the road system.

Residential buildings must snap or not snap, as needed, such that you can place several neighbourhoods in the vicinity of each other without them melding into one. If need be, you could always snap them together later on. As such, it might be prudent to provide size limits for neighbourhoods as well. At a certain point, no more residential buildings can be added to an existing agglomeration. How high this upper bound would have to be depends on the relative size of public buildings versus residential districts and is at the mercy of the developers’ needs. After all, at some point you have to stop adding features to a residential neighbourhood. The upper bound would be a way for the game designer to indicate that the neighbourhood has reached the limits of its physical expansion, even if it has not fulfilled all of its development goals yet. After all, it is the limits of a system that create the very challenge which simulation gamers crave for.

Moving with the times

Here and there, I have indicated already that this kind of game design, using organic public buildings and agglutinating residential areas and road systems, can work for representations of ancient, contemporary or futuristic cities. Here are a few more specific examples of public buildings in different time periods, what their uses were and how they developed.

All city development throughout history has been centered on neighbourhoods, on the one hand, and public buildings of a kind, on the other, be they agora, fora, markets, emporia, souks, shopping districts, courthouses, bazaars, basilica, temples… Besides these, in imperial times, monumental or palatial buildings have served many functions, not the least of which was self-aggrandizement of and propaganda for the leader(ship). Why include a governor’s mansion in your list of buildings, and assume that the governor only lives there? In reality, such buildings are full of scribes or clerks, and are buzzing with activity, as was Pharaoh’s house and the Forbidden Palace, or as is the Vatican, the Palace of Westminster and the White House. Such buildings should not only provide services to the surrounding neighbourhoods, but also employment. They might also allow for influencing different political groups, such as in the “Tropico” series.

In an Egyptian setting, the main public building would be the Pharaoh’s house/mansion/palace, which was itself part of a temple district, with priests making up the administrative caste.  Monumental buildings, such as temple complexes (think the temples of Karnak, Luxor and Bubastis), tombs (like those in the Valley of Kings) or pyramids would be central to cities where the pharaoh himself was not in residence. Entire cities grew up around such building projects. In the case of tombs and pyramids the adjacent towns would disappear again when the monuments were completed. Of course, tombs would operate very differently from temples. Temples can provide a great number of administrative functions and would be staffed by a more learned stripe of citizens, while tombs would require a large amount of skilled and physical labour, and the main bonus of the latter would be prestige for the entire city, whereas the former can provide local bonuses to healthcare and religious needs.

In an Ancient Greek setting, you would have agora, akropoleis and temple districts. These have all served many purposes over the centuries, often overlapping ones. The agora in Athens served as a marketplace and a stock exchange, and it included the Pnyx where general assemblies of the democracy were held. An akropolis was often the initial site of settlement for many of the Ancient Greek city states (such as Athens, Korinth, Eleusis, Sparta, Thebes etc.). This hill would be fortified for a time, until the settlement grew downhill. Their military use would wane – but not disappear – and akropoleis would morph into prestigious districts often dedicated to religious and administrative purposes. Temples on their own could serve as cult centres for many gods, as treasuries, and they could also be institutions of learning (cf. the Museon in Alexandria), sports (cf. Olympia’s hosting of the Olympic games), culture, oracular prediction (cf. the temple of Apollo in Delphi) and industry or healthcare (cf. the temple of Asklepios in Epidaurus).

This is an entrance to the Akrokorinth, the akropolis in Korinth, Greece. Over the centuries it was fortified to repel invaders.

There are so many ways to develop this concept for other settings: churches, castles, cathedrals, city halls and belfries (i.e. Belfort, Big Ben, Campanella) in a medieval European setting; royal districts and ziggurats in meso-american settings; longhouses and mead halls for early medieval Germanic cultures; castles and palace complexes in medieval Japanese settings; stupas and wats (i.e. different kinds of temple districts) in India and southeast Asia…

In contemporary settings, parliaments (and their environs), university campuses, airports and financial districts could join the previously enumerated kinds of buildings. Elaborating on everything that has come before, futuristic CBGs might include spaceports, space elevators and AI mainframe buildings (which would serve as administrative centres).

The transition from medieval to industrialist (and futurist) settings would change the dynamic of the building types. Once residential areas are no longer the main source of manufacturing, game developers might have to introduce more buildings to the “primary resource gatherers” type of buildings, dub them “industry”, and turn them into organic entities that grow through agglutination just as residential areas do, such that you get industrial zones. Residential areas could still agglutinate, but instead of becoming grouped based on profession, what you would get is city districts such as Soho and the West End in London, Lower East Side and Brooklyn in New York City, and the European quarter and the old city centre in Brussels. These districts might have distinct visual flavours while also providing separate cultural functions.

But is it feasible?

While it is a lovely thing to fantasize about game design in a vacuum, the real question is, of course, whether a system of organically growing neighbourhoods and non-linearly developing building sites is feasible from a programming point of view. I am not a programmer, but looking at the kinds of systems that have been designed before, it seems like most of the parts of the whole are there. All it needs is for someone to tie them together in the context of a fun game.

These are the pieces of the puzzle that I have nattered on about throughout this article and whether their implementation is feasible or not:

  • Can we have very large, even customizable buildings?
    e.g. “Pharaoh”, “Nebuchadnezzar”
  • Can we have non-linear development of buildings?
    e.g. “Townscaper”, “The Architect: Paris”
  • Can we have agglutinating buildings?
    e.g. all of the CBGs from Impressions Games. Though they were restricted to a 4 by 4 area.
  • Can we have road snapping? Can we have free-form road building?
    Yes and yes.
    e.g. “Cities: Skylines”, “Black & White 2”
  • Can we have organically developing residential areas?
  • Can we build objects inside buildings (that change their look)?

If you know of examples I haven’t mentioned that showcase these features, please feel free to put them in the comments. Can we achieve all of these features at the same time, though? Only time and iteration will tell. The hardest part will be to create the modular parts that must be knitted together in a visually arresting and pleasing manner without looking “samey”.

Technically, residential areas and public buildings should appear to be different in every playthrough. Houses that are inserted piecemeal should get incorporated into the existing design as they are, and not immediately take on the style of the surrounding buildings, and they will develop individually. If alleys are to spawn organically as well, and if citizens are to walk through neighbourhoods using said alleys, then the position of an alley will have to be sufficiently defined despite the modular and continuous development of that neighbourhood to allow accurate pathfinding and the accurate representation of a citizen walking through or into a neighbourhood.

What are your thoughts? What other synergies could there be with this kind of game design? Or would you want to implement these synergies using a different mechanic? Definitely let me know in the comments!


1. There are a few games that precede SimCity, notably the text-based  “The Sumerian Game” (1964) and its derivatives, and “Utopia” (1982). For some history of the genre, this article by Richard Moss will definitely clue you in.

2. For those interested in the classification of CBGs, this is a good read. Also, GamerZakh proposes a neat way of differentiating between different kinds of CBGs and simulation games in his video “What is a ‘City building Game’?”.

3. This puzzler aspect is part of the definition of games in general, even though there are pure puzzle games such as “Tetris “or “Bejeweled” (etc.).

4. There are also pure simulators, such as “Universe Sandbox”, that do not entail any gameplay elements, have no challenges or objectives, but merely exist to simulate a phenomenon. Such simulators are probably closer to edutainment than entertainment, but they are well worth mentioning.

5. These types of games are more readily found either as mobile games or as mini-games, and sometimes as a part of larger game projects.

6. For an analysis of medieval CBGs, see Peter Alexander Kerkhof’s 2020 article, “Why medieval city-builder video-games are historically inaccurate”.

7. See PcGamer’s 2021 article by Christopher Livingston for CBGs with a twist.

8. I guess it shows that I grew up playing lots of games from the “Caesar” series?

9. I haven’t made up my mind yet when it comes to fishing. A neighbourhood built on or close to the shoreline or next to a river could develop to become a fishing village. Fish would then be sold as a “finished product”. This is not so far from the truth, considering a caught fish undergoes quite a bit of processing before it reaches your plate, so one might imagine that the men and their sons (sorry ladies, the past was sexist) would go out on a fishing trip and upon their return the daughter would clean the catch, and the mother would hawk it on the fish market (or vice versa).
Farmland and pasture could be handled similarly, but considering that farmlands and pastures are often geographically divorced from the residential area of the labourers, it doesn’t seem like the best way of handling those particular resources.

10. For a discussion of agent-driven systems in “Cities: Skylines”, for instance, you can read this reddit thread.

11. It likely wasn’t, because women work in the home. Even if you call it “rearing the children” or “managing the household”, that’s still a job, and you’d have to pay someone else to do it for you if you didn’t do it yourself. Roman plebeian women might take on all kinds of odd jobs outside of the home too: they might open a shop, they might weave fabrics or sew clothes to sell to a shopkeeper, or they might work at the laundry around the corner… Let’s look benevolently on the developers of “CivCity Rome”: they needed a way for houses to be more needy and to have their needs be met as well, so they invented women. /cheeky

12. When I say that, I mean: I have thought about it, and so have other game designers, and I could write up an entire article on the merits and demerits of having different classes of housing to represent the different classes in a society, but it’s taken me long enough to write this article, so I won’t. I would love to hear your thoughts though.

13. Featured photo by Mikhail Nilov downloaded from Pexels.

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