Okay so I had an architect moment with the flood tunnels and forgot which way round the sentence was said (I'm a numbers guy afterall). Keep the comments coming though, they're good for the algo!

Matt the type of guy to prove myths and then call them busted

I don't think Matt knows what "busting myths" means lol Also does this mean you can stop tsunamis with tunnels?

When the myth is truth, it's confirmed, not busted

You can replace the ocean with poo, what you did wrong here was that you placed to much outlets for your "city", so all of them just spat like a bucket/day what instantly evaporated in the large bassin you tried to fill.... have the outlets somewhat near to each other, bundled up in a river and dont build too many of them or build a city that is able to supply them :D

3:43 fun fact: Redwoods are actually very fire resistant in real life so good choice in sticking with something else lol. (Yes this is just the nature nerd in me talking)

Matt’s editor really didn’t have his back with the whole Busted vs Confirmed nomenclature.

I mean if the Myth is "water can't flow through tunnels" and it's proven so, then that is "myth confirmed" not "busted" :P

The ground actually absorbs water. I suspect the sewage is just being absorbed into the ground faster than you can pump it out. That would explain why you got the tidal result. In your last mini-test it looked like you had a puddle of sewage coming up from the ground. It might be better to try on "harder" soil, because I think the terrain and if it's sand or not matters.

You could have placed the water pipe first and then the sewage outlets snap to the pipe

I feel like a better test for the forest fire/windmill one would be to have the two parallel strips, one with windmills and one without, and then start the fire at the same end. If the wind is blowing in the same direction, then it'd be interesting to time how long it took for each line to burn completely and compare the numbers.

Matt, if you ever want to test with a large population you can use the eden project in monuments which maxes out the land value causing all the buildings to upgrade and gives you way more people

Since wind turbines take energy from the wind, the wind loses energy and slows down behind the wind turbine.

There is probably a lowered water source on the actual map (in editor) that is acting like a drain taking all the sewage out of the sea.

6:15 If there's a limit to how many fire 'ticks' are allowed, there's an easy explanation for why the first fire always spreads quicker. Assuming that it picks random points on either circumference, the first fire always has a larger circumference so it will be selected more often to spread.

Just throwing this out there. Use offices to separate your high density commercial and residential. People will move in faster without the noise pollution.

I had a suggestion for the poo ocean myth. I dont think the drains add liquid sewage, they just change the water into becoming poopy. So you should let the ocean refill the land and then the drains should poopify it all, maybe

8:57 "I'm not tryin to build an efficient city, I'm just trying to put one together as quickly as possible" soo you're an architect today!?

The game has an evaporation mechanic. Go get a normal city place a single drain line a long ways from a river and all you get is some polluted land and the sewage never makes it to the river. Its a fantastic way to reclaim water filled areas. I played an "Atlantis" challenge map years ago and found this trick.

Matt: tries to pick flammable tree, picks fire retardant tree where fire is part of its lifecycle

here is a myth,, Can RCE Build an ACTUAL good city layout that WORKS with NO weird twist and turns? ;) LOVE the videos mate! Keep em coming! =D

Definitely still think this segment should be called "engineer or architect?" It would probably help Matt get "busted" and "confirmed" correct too ;)

There is currently poop water pouring into our flooded neighborhood in Central Florida due to Hurricane Ian. Looking forward to watching your videos with a new sense of understanding of what you put “people” through, lol.

I absolutely love this idea, I wish there was a game with more realistic weather and physics mechanics to test myths on

Confirms a myth: "busted!" Lmao

Even if you could make a large sea with the sewage, the sea will overflow, you need the clean water source points to controll the height of the sea to prevent floodings, so, you cant replace the sea with sewage

Myth: RCE can tell the difference between "busted" and "confirmed"

What's happening with the poop water is that the game simulates evaporation. If you can't output the water (or crap, in this case) faster than it evaporates, you just eventually reach equilibrium.

Redwood trees actually grow better with forest fire because of the fibers on their bark who are highly flamable, but the log itself is invincible to fire or lava, they also spread a lot faster because of the pinecons splitting open with heat

The thing with the wind turbine is so silly because they ran because of the wind and not with a motor so the wind is spreading the fire

you can place a long water pipe first and place the sewage on top of it instead of connecting them one by one. that's if you dont like the sound effect only ofc :)

The difference in the spread of forest fires is because there is a limit to the amount of trees that can catch on fire. The first fire will always be bigger because it got a head start. The head star makes the circle larger thus making contact with more trees. This effect would be more obvious if you didn't have a strip of forest, because the radius could expand more

i think what was happening with the poo ocean was the pumps where somehow sucking it up through the wall

Pretty sure even the MythBusters themselves once called a "they replicated the circumstance and results perfectly" result _Busted_ by accident... Also, an explanation for the water thing: Skylines doesn't actually use a particle-based water system, both the water and terrain are actually just very intricately programmed heightmaps. It's why you can't make a terrain-based tunnel (road tunnels are actually entirely separate from the terrain and have no physicality, hence water not flowing through them), why water will never "crest" over itself (think a surfing wave), and why all the Tesla Valve experiments didn't work according to fluid dynamics (which only works with particle-based water, not a heightmap simulation).

For the windmill forest fire one, you should have checked the wind speed in the area and made sure both were the same. Windmills usually get placed in the windiest areas, so that could be the actual cause.

My theory about the water in tunnels is that the game does not actually cut a hole into the polygons that make up the cliff face, and create new geometry to form an actual tunnel of polygons for the water physics to interact with. Instead, the tunnel portal geometry is setup so that the dark "interior" of the tunnel is actually just a black or very dark flat surface offset from the cliff wall geometry. This creates the ILLUSION that there is a tunnel, without actually having to model a tunnel. This would be done as a way to save on game performance, shaving off polygons and textures that wouldn't be visible anyway, helping with performance. This means, however, that while the user just assumes there is a tunnel, there actually isn't a tunnel. Much like if you draw someone standing knee-deep in snow, the artist doesn't have to draw feet, but you, the viewer of the art, assumes they subject has feet, when in fact they don't, because the feet were never drawn. You see a lot of novice artists do this with hands, where they don't know how to draw hands, so they do everything they can to hide the hands, be they in pockets, behind another person's shoulders, wearing mittens, or simply out of frame. We just assume the hands are there, because hands are normally part of the whole person. So when they hide the inside of the tunnel with the black surface trick, the game artist is assuming your brain will just assume there is a tunnel there, when in fact no tunnel exists in the world geometry. Since no tunnel exists as tangible geometry, the physics engine treats the cliff face as what it is, a solid cliff face, because the reality is there is no tunnel. Now, one could perhaps modify tunnel portals in a manner that flags them as a passable drain/source. If I were to mod it (keep in mind I have no experience with this, so forgive me if it's outside of the game engine's capability), my solution would be to make that black back plate an actual physics portal linked to the other portal. I assume these portals are already linked in a similar manner to allow traffic to pass through in a consistent manner (blue car goes in, some time passes, blue car comes out the other side). If this is the case, then you could tell the portal to allow in X volume of fluid per second, wait for the time it would take for the water to span the distance between portals given the water's rate of speed and acceleration, then generate water at the other portal in a volume, speed, and acceleration befitting the variables at play. It would still be smoke and mirrors, but it would allow for a much more convincing simulation, especially if the portals can flow both ways. If I had to write the code myself (again, I really haven't much coding experience), I would study how Valve achieved this in Portal 2 with their fluid through portal physics, because that's basically what the mod would be doing, but with a delay between when something goes into a portal in relation to when it exits a portal. In the Portal games, the travel between portals is instantaneous. If a mod was made to apply this tech for the fluids to pass through, a modifier, as I mentioned earlier, would be applied to give the illusion that the fluid has traveled a distance rather than instantly coming out the other end. I know this was a long comment, and I appreciate you for reading this far. I don't even own a copy of this game, but I do have a basic understanding of how game developers cheese the system to give the illusion something is there when it really isn't. I mean, that is the nature of games, that all geometry and textures you see are a facade, an illusion banking on your gullible brain to assume there is substance where there isn't any to be found. It's not malicious, it's just practical given the limitations of hardware and manpower to produce the assets, and it's acceptable because our brains are willing to believe the lie for the sake of entertainment and immersion.

Very cool. I like these experiments better than just straight game play. It is the engineer in me. 😊

I think it only works if its MIXING with the sea/lake/river water. If you are dumping your poo into an empty area it likely just falls through the map? Gotta mix it together like a giant toilet! :D

For the fire test. As an aspiring engineer wouldn’t you make two long stretches of wood one with windmills n one without. Start a fire on one end for both (starting at the windmill side) then watch and see. If it’s delayed repeat the test with and without while starting only at ONE point. Then compare when the fire starts and how fast it moves vid to vid. Just a thought

The tunnel thing makes a lot of sense. Basically, as far as the simulation is concerned, a tunnel portal is a special kind of wall that destroys vehicles that "drive" into it and then recreates them somewhere else after an appropriate time delay (because it'd be a lot of extra work for minimal payoff to implement real tunnels). The water code basically hits it, goes "ah, a wall", and doesn't flow through - though, given how we've seen water flow through walls before, water MIGHT go through a short enough tunnel.

Windmills: use wind to be powered Also Matt expecting the forest fire with the wind blowing against it to move faster...

oO Myth: Water CAN NOT flow through tunnels... RCE: finds out it cant go through vanilla tunnels... also RCE: "Busted". Oo what? that would be true tho. it canNOT flow through it. so myth confirmed, it cant. HUH? At least he found out by himself that Turbines dont Blow.... i hope...

Matt is the type of guy who drains the entire ocean and still have a tiny city being thirsty

On the first myth, it looks like tunnels in City: Skylines are built with flood gates. Some tunnels IRL have them, particularly if it's a tunnel that goes through a levee.

Matt, redwoods are notoriously DIFFICULT to burn. That's why their wood is so prized in construction. Just FYI And California has two of the three species: Coast Redwood and Giant Redwood (Sequoia), though Giant Redwoods are not great building materials.

Well the poo evaporates just like water in the game so it's very hard to fill it with a 100% poo composition. In engitopia it was contaminated water flowing through the river so it had about a 60-80% poo composition. (to measure that just place a water pump and open the pollution tab.)

I suspect that the wind in the forest fire test is simply stronger on the left side in the sim. (I'm not sure if the sim even sets a direction to the wind, given there are no arrows when you examine the wind layer in the game.)

Matts the type of guy to ask "Is anyone gonna fill that sea with poo?" and not wait for an answer

Matt I love you so much. I've been watching some of your first videos and I hope to be a civil engineer when I grow up. You have taught me so much even if half of it is just joking lol. Thank you so much keep making amazing videos.

If anything, windmills should SLOW the wind speed behind them, as the very nature of a windmill is to convert the kinetic energy of wind into electrical energy by way of rotational force spinning magnets. Maybe someone else can word that better than I can. Point is, a windmill creates drag, not thrust. Of course, the cross section of a windmill is designed to be aerodynamic to reduce stress on the supporting structure, and try to limit the drag as much as possible to the actual airfoils. So I'd imagine the drop in wind speed would be negligible per windmill. Also, it would seem unwise to put windmills near trees, because trees are excellent at slowing wind (why you see thick, tall, leafy trees planted along the borders of farms, to aid in reducing soil erosion during dry seasons, among other things). If you place windmills near trees IRL, the windmill won't be much use if the trees are upwind.

I wonder if there is an architect that lurks here and get hit with "hello fellow engineers" at every start of a video

So I think what happened with the ocean thing was twofold: 1. The ground "absorbs" some water. This isn't a mechanic as much as a quirk with the weird way Cities uses heightmaps to represent water. Basically, what water considers ground and where the actual ground is are not always the same place, especially in extreme terrain, like the giant walls. This is likely why the pumps seemed to be making no sewage, even in your small-scale test. 2. The game does have evaporation as a mechanic. Like real evaporation, the more surface area, the faster the evaporation. And, weirdly enough, sewage, when disconnected from water, evaporates faster than water (obviously, this isn't true for the real world, this is likely meant to prevent you from accidentally flooding towns with poop or something). Altogether, this was what was preventing you from replacing it. You'll notice how the poop seemed to be filling initially, fully subsumed the small bits of water that had leaked through, and then receded very quickly. Suddenly, the sewage was only connected to sewage and the game's "The player has placed a sewage outlet in a dumb place" alarms started ringing and the game started evaporating the disconnected sewage rapidly. It only evaporates the surface area, but almost all of the sewage being released is surface area. This is also why you have been able to fill up isolated areas before. Small surface area means it evaporates much slower. Weirdly enough, a better way to replace the ocean would probably be to close off a normal map with walls, but leaving the water, and then filling that with as much poop as you can.

Every day I watch his videos, and everyday I thank my lucky stars that this man chooses to be a youtuber. I mean, gods help us all if he ever decides to go back to his real job 😂

Hey Matt, you should definitely try the last one again, because by just the way the game treats sewage, means you absolutely could create a sea of poo. The problem you had was kind of two fold. First you had too many inlets and outlets that the game couldn't keep track of how much should be going in or out in any particular location. Plus I'm betting the 81 Tiles mod didn't help you since the closer you get to the edge of the map, the stranger things act. The second part of your problem, and the main one was that the poo was getting pulled back up into the gigapumps. Their area of effect is larger than the wall you have them sitting on. You could have verified the poo getting pulled back into the system if you didn't have infinite demand on, as people would start getting sick and dying and/or leaving the city, plus a hospital probably would have helped in both respects. If you want to save the world you already have I would suggest killing half of those gigapumps, and ALL of the old outlets. Widen that terrain wall you've built, but honestly it just needs to be about twice it's current width to avoid the activation column of those pumps. Have the new outlets spill out over by that jagged hill, that I would hesitate to call a mountain even in real life, and you should see success. I also saw a comment about using The Eden Project, and that would definitely help your city fill up your sea faster. I would also suggest getting the mod that allows you to manipulate the sea level and add water sources in simulation. Not for any particular reason, but I think it'd make your life easier at times. Good luck, Dude!

An engineer of physicality. An architect of words.

No chance you read this, but I have noticed that water seems to glitch through walls when there are sharp edges. That's why water can appear out of nowhere, it's traveling through the surface terrain. The game land is loaded in as a surface, not a solid, and physics only applies in the triangulated matrix that makes up that surface. Your landscaping tools with "hard edges" are creating areas where it's easier to glitch through walls. I believe it's because this game has a concept of groundwater, both as water wicking into the land and springing up out of it, and that's probably accomplished by supporting the physics for some of the water to pass through land and still exist underneath. Anyway, I suggest trying out the the ramp tool to create inclines instead of cliffs to keep the water in, maybe test what angles work best, or build everything out of dams... Keep up the great content @RCE!

This will make an awesome series!

I think there is a question with the Forest Fire and the Wind Turbines left unanswered. While it shouldn't have an effect on in the nature in which is spreads, would it increase the power output of the turbine? And would this be a viable way to store power across the world. Only burn forests responsibly.

RCE not even able to recreate a 17 year old show concept. If the myth was »water doesn't flow through tunnels« and then you build tunnels and the water doesn't flow through them, the myth is confirmed, not busted. What an architect…

I think what happened was that since your city wasn’t functioning that well, then they didn’t have any real poop to fill with. The pumps might just show a stream of water coming out but not actually do anything until people in the city use it for real. I’m assuming this because when you build a regular functioning city, the pollution doesnt start happening until a lot of people have moved in

It is a good day in Engitopia when Matt uploads

Water might be able to go thru some modded road tunnels which have fully rendered tunnels.

Yesterday Timberborn, today it is city Skylines, I am Happy

For the forest fire one you could’ve had a wide strip, of the same forest, and on the same side of the strip, half has wind turbine behind it whilst the other half doesn’t, and leave the other side of the strip without anything

Myth: RCE is actually a bridge architect. Bust it.

7:20 amazing you managed to recreate Cleathorpes!

Mate....busted means it's false. Discovering a myth is true (water doesn't flow threw tunnels) means the myth is confirmed...an architect would know this

Hi Matt, here's a bridge myth... You can't build/places bridge in City skyline, which would get a 10/10 rating from RCE ... Much love an keep up your work! :)

I think the variable in the forest fire myth is that the wind direction changed and it could be that the one that would have to spread in the direction going into the wind is spread slower than the one traveling in the same direction as the wind

The one with the windmills and forest fires was a bad test because you didn't set up a separate forest as the control. The wind speed/direction itself could/should be playing a factor. If it's blowing the fire toward the trees then they should light faster, and if it's blowing the fire away from them then they should light slower. So you should have set up two forests, one with windmills and one without, and then lit the same end of each to see what would happen.

3:18 WINDMILLS DO NOT WORK THAT WAY! GOODNIGHT!

In North America at least, the oak trees, pine trees, and redwoods all come from fire-adapted ecosystems. In their mature state, none of them are particularly likely to burn without significant fuel loading underneath.

Myth: Big ol windy energy bois are windmills No. They are wind turbines. Windmills are mills. They grind corn or wheat or whatever else. Turbines create usable energy constantly while in operation. Giant fan looking thing≠windmill.

the Poocific Ocean was seriously the most engineery engineering feat, truly an advancement to humanity

Given wind drives turbines, wildfires will spread faster in areas that are suitable for wind turbine installations as those areas will have higher average wind speeds, for faster spreading flames. If the wind is accurately simulated then a fire in the centre of a big square of trees should spread faster in the direction air would be exiting the wind turbine, and a race between a fire without wind turbines on the leading edge, vs one with them, should actually spread faster (with enough turbines in front of the other) as the turbines take energy out of the wind meaning slightly slower winds behind them (in theory).

the whole sewage and water screenshot reminds me of the time my fiance first played this game. she ended up putting a sewage drain up stream from a water facility or something like that lol she had a nice city otherwise, until the population started dropping like flies due to the water. dang near decimated the whole city before she finally figured out the source, was kinda interesting to see and funny once i realized what she had done lol she felt horrible for the citizens of her doomed city lol

What buildings can survive underwater? Can you make the self feeding dam? Can you sink ships?

Can You build a City where it's always dark? Maybe underground? Or something that is coverd with thousands of bridges to block the sunlight? "The Line" could need a roof... just saying.

The wind turbine myth: Did that myth originate because people think wind turbines are big fans that create wind...? I can't imagine why else someone would think a turbine would fan the flames.

You should totally do a cities skylines collab with Adam Savage of Mythbusters. What a time that would be 😂

Suggestion for another video; could you actually stop a tsunami using a bunch of tunnels, using the same principle as in the first segment ?

12:56 "Yes, there is water in the sea" - Real Civil Engineer

I feel like you need another shot at fecal bay but maybe try adding the poo to the water and see if you can push all the water out of it.

Hey Matt! Big fan my family and I crack up watching your videos. Myth/Video: Can you build London/New York City in Cities Skylines?

Try adding just a couple of the cleaners. Looks like 100% sewage is the problem. Must evaporate quickly? Get it filled up and remove the cleaners?

as for the tunnel floods. the advanced cities have an automatic floodgate which can close whenever a flood is detected

I'm kinda miffed that the tunnels are square. Round tunnels are just so much more aesthetic.

I'd bet on the water through tunnels thing that maybe for game performance, the tunnels aren't rendered as actual spaces with an air passage until you select to delete them or something. Can you ride first person on a car through a tunnel or does it force your point of view above the ground? I don't have the game installed to try it.

Vertical cliff faces are almost always bugged when it comes to water physics in CS, try a sloped hill rather than a vertical cliff face.

Maybe the **** was simply spreading too much and "evaporating", try with a bunch of **** lakes to start with then create a exit path from the lakes into the "sea", maybe that'll work?

4:00 Wind turbines are just big fans for circulating air. Wind never existed before them. The still air was excruciating.

If anything the wind in the area of the fire makes it spread faster...not the windmills. They don't push air. Air forces them to turn and if anything there's a breeze out the back of them but it's alrdy windy. Windmills don't make the wind blow harder.

I remember seeing a video years ago were a guy's entire city was burning down and he had a giant waste pit so he just flooded his city with the waste water. City skylines is a fun game.

*16:10** looks like it tried to get an item from a list/array that doesn't exist.* Very common with arrays and lists.

so, can you stop a tsunami with tunnels?

the best part of the windmill thing is that windmills are moved by air, they don't move air

omg i never realized that some people think that wind turbines speed up air. also it looks like fire spread is wind dependent, so if the wind is blowing the fire ofc the turbines are going to be pointing in the same direction

Semi myth. Can you get stable power out of a hydro dam that pumps the outflow back above itself as a contained system? I know the hydro dam produces more power than the pumps use to refill it. But in my experiments it was never stable. I think evaporation drains the water.

I still believe in the poop ocean, I just think you had too much on one map so it couldn't handle it. Maybe draining the whole ocean did it. Perhaps draining the ocean slowly while replacing it with poop would fix the issue. Would love to see you try anyway.

Sewage evaporates. Depending on the size of your city, there is a max surface area of lake you can maintain