Sure they teased that they've made their own solution, but I think Junxions should scratch the itch of most of us here interested in this kind of game.
There's so many things in games that are taken for granted at play time but which actually take a lot of thinking and work to get right. Roads for instance aren't something which your typical player will look too closely at... but they will notice if they look or behave in a way that seems wrong.
I've been playing Kingdom Come 2 of late, and I find it's natural to just kind of take the world they've created for granted - just like we do the real world. But when you actually stop and look you have to consider that every one of the finely crafted details was built by someone's sweat and tears, be it artists, programmers, or designers at edit time.
No wonder it's an industry of crunch, the work involved can be uniquely daunting.
Another area of hidden complexity is doors in video games. Almost no game has life sized doors because they introduce gameplay issues, almost all doors in video games are at least 30% bigger than in real life and you see an overabundance of sliding doors vs swinging doors because of the complexity swinging doors bring to video game physics.
The bit about the clothoid finally made me understand the odd shape of highway junctions. I always wondered why they want me to enter turns fast and then slow down progressively until the turn becomes a new straight. Unfortunately sometimes that straight is the highway, and they should give us plenty of space to build up speed and match the traffic inside the highway. Sometimes they do, sometimes they don't.
Ahhh.. this is a writer after my own heart. Absolutely brilliant write-up. I had the same obsession with roads, from SimCity onward; they're the circulatory system of any city, and never in the history of cities or the history of circulatory systems have the vessels been straight lines. The streets of a European or Asian village usually tell a story about how roads were built over the fastest footpath from the outskirts to the center, then over time amended to go around some buildings that were built in the way. Whereas roads in rural parts where I come from run in long straight lines and then suddenly swerve to get around a piece of land that a farmer wouldn't sell. But grids only exist in some parts of the few cities that were built mostly by colonial powers, or developed later with master planning. And even those grids usually split from their original orientation to becoming north-south at some point in in the city's development, leading to the interesting downtown triangle blocks of cities like Portland, San Francisco, Los Angeles, Seattle, New York. Other cities started to grid around their core footpath villages, like Madrid, Barcelona.
The cities I find the most interesting (for roads) are the ones which kept gridding out in new directions to follow the course of a river. Cities like Buenos Aires, New Orleans, and Saigon, where the original paths followed curves around the river bends, resulting in multiple intersecting grids.
The intersections and division boulevards between grids are, of course, the most beautiful and architecturally interesting parts of any city. They are where the blocks are strangely shaped and the buildings can't be rectangular, and usually where every inch of land is at a premium as well. It would be nice if a city-builder could simulate that aspect of urban growth: The shift from village center to grid, and old grid to new grid.
Can relate the fascination with roads I use to like drawing them loads as a kid. I find Satisfactory the most satisfying for building transport systems (and building generally) your work incorporated into a mod for that would be really cool.
Be like the Romans - make them all straight lines :-)
Of course the Romans didn't give a shit who's property rights they might be violating. I live in Lincolnshire UK, where Roman roads are still used. The last one that got changed was years ago when they had to put a kink in Ermine Street (now the A15) at RAF Scampton when they extended the runway to accommodate Vulcan bombers.
The romans did care about property lines! Romes’ second aqueduct was held up when land owner Crassus refused to give up private land for its construction. Check out the article for a fascinating read: https://en.wikipedia.org/wiki/Roman_aqueduct
In my area, streets are often church tower to church tower. From the middle ages. You can nowadays drive these streets and the middle line indicators align perfectly with the church tower showing up. I think the church /church based government share that property right understanding of the Romans :)
I studied urban planning back in the university and one of the classes was road design. Though I forgot most, one part of the class was about how to design roads with curves that's safe for cars. This post just brought that memory back to me.
My version of OP's roads problem is blob autotiling - how tiles connect to their neighbors. 256 possible neighbor combinations reduce to 47 valid patterns once you realize corners only matter when both adjacent edges are present. You paint a semantic type like "wall", the system resolves the right tile from those 47 patterns - but painting one tile cascades outward, neighbors re-resolve, which triggers their neighbors, and you're tracking stale state to keep it all consistent. Same underlying problem as road segments affecting connected intersections.
I've been trying to make this as easy as possible for non technical people to draw terrain in craftmygame (the game engine I'm building) here's what the terrain painting looks like in the editor so far : https://youtu.be/bFrUYM2t3ZA?si=tw1LqBWR7Uyn08lR&t=37
I was fascinated by them since reading a guide for Cities: Skylines that said that roads were like trees. There's a trunk that moves large amounts of nutrients and little branches that distribute the nutrients to the leaves. Such simple rules, but such complex and deterministic results.
This is a really interesting approach but I'm curious to see how it translates to the actual mesh extrusion, or whatever 3d technique they adopt. It's relatively easy to do this in 2d, it's the 3d solution that accommodates terrain variation that introduces the real explosion of complexity
Another aspect of these games is the subtle scale issues that aren’t readily apparent - even the newest biggest city simulators are fractions of the size of a real city.
Road and rail curves are massive and it’s hard to understand just how big they are without having to actually walking them.
You can find in developer notes for city sims that sometimes they've tried to keep sizes of roads and parking lots to scale, and then they realize it's all low density and uninteresting, kind of like real aerial photography of a typical US city.
So the difference in scale between real life and the sims is 100% on purpose, as more realism makes the game worse. Just like they don't ask for a long permitting system for anything to get built, or demand a decade of discussion and probable lawsuits before you can move move a road, or rebuild an intersection.
Having played many city building games though I’ve always desired more depth and realism. Like the more I play them the more I want out of them. I wish power lines were limited in capacity and had to be stepped up and down via transformers (Workers & Resources does this) I wish I could make decisions about every intersection and every lane (cities skyline mods allow this) etc. Anyway I think there’s an audience for more realistic games in general, even if most people would find them less fun.
I regularly drive what I thought of as a quite winding road. Visitors drive it cautiously. It was funny one time looking at the satellite view and thinking "Wait, where is the tight bendy section?" Everything looked like very gentle curves; probably closer to straight lines.
I love SimCity 2000 and these roads look really cool but I'd really like to see a city-builder go in a different direction.
One of the biggest problems with North American cities is their endless, car-centric suburban sprawl. SimCity games may be really fun to play but they seem to reinforce this problem and anyone who grows up playing them will not learn about alternatives for more livable cities.
New Urbanism, traditional neighbourhood design, streetcar suburbs, one-way streets, bike paths, walking paths, mixed-zone walkable villages (light commercial with residential), smaller single-family houses and duplexes, triplexes, houses behind houses. Many of these are older and more traditional techniques to yield higher density neighbourhoods without building up to large apartment buildings.
It would be really cool to see a game that focused more on creating these kinds of realistic and aspirational living spaces instead of the usual cookie-cutter suburbs linked up by huge roads and a large downtown core.
> SimCity games may be really fun to play but they seem to reinforce this problem and anyone who grows up playing them will not learn about alternatives for more livable cities.
That's because SimCity is not a tool for preaching your personal opinions of what makes "more livable cities" to people who more often than not want to design semi-realistic, typical cities in an entertaining strategy game.
If you want to make your perfect city builder, go ahead, it's easier than ever now for somebody to create a game. Just don't expect everybody else to share your view of "aspirational", more so if you actively punish traditional city structures.
There are plenty of “chill and peaceful” city and town builders that trade realism for prettier, more idealized places.
In more simulation-focused games, cycling and walking paths are often available, and you can use them, but they come with many of the same constraints they face in the real world. In practice, that means they are usually not efficient as the primary way to move large numbers of people across a large city.
Reading your comment, it sounds like you want a game that is realistic in most respects, but treats transportation differently, in a way that makes your preferred options the optimal strategy. That is going to be hard to find, since transportation is a core part of city-building sims, and developers tend to pick either realism or a more utopian/fantasy model rather than mixing both in a single game.
That's not what I want at all. I want a more realistic sim that deals with issues such as sprawl, food deserts, transportation elasticity of demand, mental health issues (and their impact on crime and productivity), and a network-flow theoretical model of transportation and commuting contributes to all this. Building a bunch of sprawling suburbs that feed into a dense downtown core should make your citizens' commute times shoot way up and lead to misery.
A well-built large city isn't just going to be 100% biking and walking paths, it's going to have streetcars, light rail transit, subways, and buses as well as roads with cars. The difference is that people shouldn't be forced to commute across the entire city to get to work because you decided to cram all of the commercial zoning into one downtown core.
Car-centric transportation is not efficient. Not remotely. They have absolutely terrible bandwidth, and they balloon the size of cities apart the more you try to increase the speed to bring them closer together.
If you think Simcity and Cities: Skylines are realistic depictions, then ask yourself why Simcity famously has no visible parking whatsoever (or don't: the devs are on record saying they excluded it because it made the cities look terrible, there's no need to speculate here), or ask yourself why Cities: Skyline added car pokeballs (where drivers get out of the car and put the car in their pocket) or straight-up delete cars when traffic gets too heavy.
The original SimCity was perfection - you could build no roads and nothing but rail! ;)
Cities Skylines with all the DLC and the right transportation mods gets pretty “realistic” in that you can build a transit paradise but the car still exists.
[citation needed] that some combination of "New Urbanism, traditional neighbourhood design, streetcar suburbs, one-way streets, bike paths, walking paths, mixed-zone walkable villages (light commercial with residential), smaller single-family houses and duplexes, triplexes, houses behind houses." is not in fact optimal! (For certain objective functions)
When I played Sim City, I gladly built super-dense neighborhoods with high-rises facing parks, and mass transit, Le Corbusier style. One reason was that they brought in enormous income, another, that they looked cool.
Those areas aren't better to live in. They're just older parts of older towns so they don't have much wiggle room. The wiggle room was amazing for the more modern countries, except now we wiggle in a different direction too. An equal middle can be seen in Asian cities in Korea and China. They mix high density with high quality of life and little self sacrificing.
Neither US or Europe do living areas well due to their historical constraints.
They were aware of the problem and they covered it up, rather than try to show better ways of living. It’s unintentional propaganda for the crappy ways we build our cities. It’s worse than if they’d just show things how they really are.
People are totally entitled to like what they like, and that's OK. Everyone has something that works for them, and this world has a great variety of options available but the "car-centric suburban sprawl" is linked to various negative mental and physical health consequences. Negative health consequences, IMO, isn't "just as livable".
As a simple example, when people walk more during commuting instead of drive, they tend to be healthier. There are other more nuance (but studied) impacts, such as increased car accidents, mental impacts from increased isolation, etc. In America, there is even a correlation between how car-centric a community is and how often individuals are willing to seek out healthcare (even when accounting for access and affordability).
The author might get a kick out of an upcoming game called Junxions, which is a sandbox game to just do that... create road junctions.
The subreddit is here: https://www.reddit.com/r/Junxions/
Sure they teased that they've made their own solution, but I think Junxions should scratch the itch of most of us here interested in this kind of game.
There's so many things in games that are taken for granted at play time but which actually take a lot of thinking and work to get right. Roads for instance aren't something which your typical player will look too closely at... but they will notice if they look or behave in a way that seems wrong.
I've been playing Kingdom Come 2 of late, and I find it's natural to just kind of take the world they've created for granted - just like we do the real world. But when you actually stop and look you have to consider that every one of the finely crafted details was built by someone's sweat and tears, be it artists, programmers, or designers at edit time.
No wonder it's an industry of crunch, the work involved can be uniquely daunting.
Another area of hidden complexity is doors in video games. Almost no game has life sized doors because they introduce gameplay issues, almost all doors in video games are at least 30% bigger than in real life and you see an overabundance of sliding doors vs swinging doors because of the complexity swinging doors bring to video game physics.
https://lizengland.com/blog/the-door-problem/
https://www.ign.com/articles/putting-doors-in-video-games-is...
This was also confirmed by a Valve developer recently about a bug in HL2:
https://mastodon.gamedev.place/@TomF/115589925206309168
Articles like these are the reason I continue to check hackernews.
Author please keep writing.
The bit about the clothoid finally made me understand the odd shape of highway junctions. I always wondered why they want me to enter turns fast and then slow down progressively until the turn becomes a new straight. Unfortunately sometimes that straight is the highway, and they should give us plenty of space to build up speed and match the traffic inside the highway. Sometimes they do, sometimes they don't.
Ahhh.. this is a writer after my own heart. Absolutely brilliant write-up. I had the same obsession with roads, from SimCity onward; they're the circulatory system of any city, and never in the history of cities or the history of circulatory systems have the vessels been straight lines. The streets of a European or Asian village usually tell a story about how roads were built over the fastest footpath from the outskirts to the center, then over time amended to go around some buildings that were built in the way. Whereas roads in rural parts where I come from run in long straight lines and then suddenly swerve to get around a piece of land that a farmer wouldn't sell. But grids only exist in some parts of the few cities that were built mostly by colonial powers, or developed later with master planning. And even those grids usually split from their original orientation to becoming north-south at some point in in the city's development, leading to the interesting downtown triangle blocks of cities like Portland, San Francisco, Los Angeles, Seattle, New York. Other cities started to grid around their core footpath villages, like Madrid, Barcelona.
The cities I find the most interesting (for roads) are the ones which kept gridding out in new directions to follow the course of a river. Cities like Buenos Aires, New Orleans, and Saigon, where the original paths followed curves around the river bends, resulting in multiple intersecting grids.
The intersections and division boulevards between grids are, of course, the most beautiful and architecturally interesting parts of any city. They are where the blocks are strangely shaped and the buildings can't be rectangular, and usually where every inch of land is at a premium as well. It would be nice if a city-builder could simulate that aspect of urban growth: The shift from village center to grid, and old grid to new grid.
Can relate the fascination with roads I use to like drawing them loads as a kid. I find Satisfactory the most satisfying for building transport systems (and building generally) your work incorporated into a mod for that would be really cool.
Be like the Romans - make them all straight lines :-)
Of course the Romans didn't give a shit who's property rights they might be violating. I live in Lincolnshire UK, where Roman roads are still used. The last one that got changed was years ago when they had to put a kink in Ermine Street (now the A15) at RAF Scampton when they extended the runway to accommodate Vulcan bombers.
The romans did care about property lines! Romes’ second aqueduct was held up when land owner Crassus refused to give up private land for its construction. Check out the article for a fascinating read: https://en.wikipedia.org/wiki/Roman_aqueduct
In my area, streets are often church tower to church tower. From the middle ages. You can nowadays drive these streets and the middle line indicators align perfectly with the church tower showing up. I think the church /church based government share that property right understanding of the Romans :)
I studied urban planning back in the university and one of the classes was road design. Though I forgot most, one part of the class was about how to design roads with curves that's safe for cars. This post just brought that memory back to me.
Thank you very much... Ineffably magnificent, as always...
Related: https://www.pushing-pixels.org/2014/04/04/the-craft-of-scree... (The craft of screen graphics and movie user interfaces - interview with Jorge Almeida...)
> And they are also… a math nightmare. Differential geometry. Integrals. Oh my… Which is probably why most games don’t even dare.
Wonder if cubic parabola (used by some railways, and visually near indistinguishable from clothoid) has easier maths.
My version of OP's roads problem is blob autotiling - how tiles connect to their neighbors. 256 possible neighbor combinations reduce to 47 valid patterns once you realize corners only matter when both adjacent edges are present. You paint a semantic type like "wall", the system resolves the right tile from those 47 patterns - but painting one tile cascades outward, neighbors re-resolve, which triggers their neighbors, and you're tracking stale state to keep it all consistent. Same underlying problem as road segments affecting connected intersections.
I've been trying to make this as easy as possible for non technical people to draw terrain in craftmygame (the game engine I'm building) here's what the terrain painting looks like in the editor so far : https://youtu.be/bFrUYM2t3ZA?si=tw1LqBWR7Uyn08lR&t=37
Timely article for me! I just went through this in my little SimCity remake for MicroPython:
https://github.com/chrisdiana/TinyCity/blob/6c3a7337788655b5...
[Adds “clothoid” to vocabulary]
One game that had a different perspective (first person mmo), but a fun network of road building in a simulated wilderness .. Wurm Online
I was fascinated by them since reading a guide for Cities: Skylines that said that roads were like trees. There's a trunk that moves large amounts of nutrients and little branches that distribute the nutrients to the leaves. Such simple rules, but such complex and deterministic results.
This is a really interesting approach but I'm curious to see how it translates to the actual mesh extrusion, or whatever 3d technique they adopt. It's relatively easy to do this in 2d, it's the 3d solution that accommodates terrain variation that introduces the real explosion of complexity
https://www.redblobgames.com/articles/curved-paths/
Everyone is raving about this article. It feels so much like a tease to me. Maybe I'm just impatient idk.
I'm with you. I hope that the other posts will also pop up here.
Another aspect of these games is the subtle scale issues that aren’t readily apparent - even the newest biggest city simulators are fractions of the size of a real city.
Road and rail curves are massive and it’s hard to understand just how big they are without having to actually walking them.
You can find in developer notes for city sims that sometimes they've tried to keep sizes of roads and parking lots to scale, and then they realize it's all low density and uninteresting, kind of like real aerial photography of a typical US city.
So the difference in scale between real life and the sims is 100% on purpose, as more realism makes the game worse. Just like they don't ask for a long permitting system for anything to get built, or demand a decade of discussion and probable lawsuits before you can move move a road, or rebuild an intersection.
Having played many city building games though I’ve always desired more depth and realism. Like the more I play them the more I want out of them. I wish power lines were limited in capacity and had to be stepped up and down via transformers (Workers & Resources does this) I wish I could make decisions about every intersection and every lane (cities skyline mods allow this) etc. Anyway I think there’s an audience for more realistic games in general, even if most people would find them less fun.
At a certain point these simulators would be so intense that your joy for the game could be your joy for real employment in a city :)
The statement reversed, you might loose your joy because working in the game is no longer fun.
I get you but just want to say: careful what you wish for :)
I regularly drive what I thought of as a quite winding road. Visitors drive it cautiously. It was funny one time looking at the satellite view and thinking "Wait, where is the tight bendy section?" Everything looked like very gentle curves; probably closer to straight lines.
Cool shit!
> Do 99% of city-builder players care what shape the corner radius of the intersection has? Most likely, no.
Maybe not... but out of all the players who care corner radius of roads in games, 99% of them probably are into city-builder!
The tech seems really cool, but the road showed in the examples is not any less insane, like, why?
Their animated gif at the very end of their own tech seems very sane?
I wish they'd actually shown more/talked about it though.
That's the point? Even though they are complex, the improved roads all use circular arcs which guarantee a baseline of good drivability.
I love SimCity 2000 and these roads look really cool but I'd really like to see a city-builder go in a different direction.
One of the biggest problems with North American cities is their endless, car-centric suburban sprawl. SimCity games may be really fun to play but they seem to reinforce this problem and anyone who grows up playing them will not learn about alternatives for more livable cities.
New Urbanism, traditional neighbourhood design, streetcar suburbs, one-way streets, bike paths, walking paths, mixed-zone walkable villages (light commercial with residential), smaller single-family houses and duplexes, triplexes, houses behind houses. Many of these are older and more traditional techniques to yield higher density neighbourhoods without building up to large apartment buildings.
It would be really cool to see a game that focused more on creating these kinds of realistic and aspirational living spaces instead of the usual cookie-cutter suburbs linked up by huge roads and a large downtown core.
Do we really need to jump onto a tangent about evil cars and evil car infrastructure on a post about b-splines and curve sections?
Everything in the article applies equally to trains and rails.
We get enough complaining about evil car-centric city designs on the posts directly about cars thanks.
I think GP is simply identifying a potential popular niche that could be satisfied in a future city builder game, which seems quite on topic.
> SimCity games may be really fun to play but they seem to reinforce this problem and anyone who grows up playing them will not learn about alternatives for more livable cities.
That's because SimCity is not a tool for preaching your personal opinions of what makes "more livable cities" to people who more often than not want to design semi-realistic, typical cities in an entertaining strategy game.
If you want to make your perfect city builder, go ahead, it's easier than ever now for somebody to create a game. Just don't expect everybody else to share your view of "aspirational", more so if you actively punish traditional city structures.
There are plenty of “chill and peaceful” city and town builders that trade realism for prettier, more idealized places.
In more simulation-focused games, cycling and walking paths are often available, and you can use them, but they come with many of the same constraints they face in the real world. In practice, that means they are usually not efficient as the primary way to move large numbers of people across a large city.
Reading your comment, it sounds like you want a game that is realistic in most respects, but treats transportation differently, in a way that makes your preferred options the optimal strategy. That is going to be hard to find, since transportation is a core part of city-building sims, and developers tend to pick either realism or a more utopian/fantasy model rather than mixing both in a single game.
That's not what I want at all. I want a more realistic sim that deals with issues such as sprawl, food deserts, transportation elasticity of demand, mental health issues (and their impact on crime and productivity), and a network-flow theoretical model of transportation and commuting contributes to all this. Building a bunch of sprawling suburbs that feed into a dense downtown core should make your citizens' commute times shoot way up and lead to misery.
A well-built large city isn't just going to be 100% biking and walking paths, it's going to have streetcars, light rail transit, subways, and buses as well as roads with cars. The difference is that people shouldn't be forced to commute across the entire city to get to work because you decided to cram all of the commercial zoning into one downtown core.
Car-centric transportation is not efficient. Not remotely. They have absolutely terrible bandwidth, and they balloon the size of cities apart the more you try to increase the speed to bring them closer together.
If you think Simcity and Cities: Skylines are realistic depictions, then ask yourself why Simcity famously has no visible parking whatsoever (or don't: the devs are on record saying they excluded it because it made the cities look terrible, there's no need to speculate here), or ask yourself why Cities: Skyline added car pokeballs (where drivers get out of the car and put the car in their pocket) or straight-up delete cars when traffic gets too heavy.
The original SimCity was perfection - you could build no roads and nothing but rail! ;)
Cities Skylines with all the DLC and the right transportation mods gets pretty “realistic” in that you can build a transit paradise but the car still exists.
[citation needed] that some combination of "New Urbanism, traditional neighbourhood design, streetcar suburbs, one-way streets, bike paths, walking paths, mixed-zone walkable villages (light commercial with residential), smaller single-family houses and duplexes, triplexes, houses behind houses." is not in fact optimal! (For certain objective functions)
When I played Sim City, I gladly built super-dense neighborhoods with high-rises facing parks, and mass transit, Le Corbusier style. One reason was that they brought in enormous income, another, that they looked cool.
Those areas aren't better to live in. They're just older parts of older towns so they don't have much wiggle room. The wiggle room was amazing for the more modern countries, except now we wiggle in a different direction too. An equal middle can be seen in Asian cities in Korea and China. They mix high density with high quality of life and little self sacrificing.
Neither US or Europe do living areas well due to their historical constraints.
It's subjective but many of us strongly disagree.
And, of course, the fact that the areas you say "aren't better to live in" also tend to be extremely expensive doesn't make a lot of sense.
The creators SimCity itself were aware of the problems you mention. Ever notice how there's no parking lots?
https://humantransit.org/2013/05/how-sim-city-greenwashes-pa...
They were aware of the problem and they covered it up, rather than try to show better ways of living. It’s unintentional propaganda for the crappy ways we build our cities. It’s worse than if they’d just show things how they really are.
this is definitely doable in CS (+mods), search YouTube for "cities skylines European" or something like that.
you need "plop the growables" and "move it" mods at minimum to nudge all the buildings close together.
> One of the biggest problems with North American cities is their endless, car-centric suburban sprawl.
Most people consider that a benefit. It's just as livable as anywhere else. Just different.
> It's just as livable as anywhere else
People are totally entitled to like what they like, and that's OK. Everyone has something that works for them, and this world has a great variety of options available but the "car-centric suburban sprawl" is linked to various negative mental and physical health consequences. Negative health consequences, IMO, isn't "just as livable".
As a simple example, when people walk more during commuting instead of drive, they tend to be healthier. There are other more nuance (but studied) impacts, such as increased car accidents, mental impacts from increased isolation, etc. In America, there is even a correlation between how car-centric a community is and how often individuals are willing to seek out healthcare (even when accounting for access and affordability).