How to CLIMB THE LEADERBOARDS in Poly Bridge 2 using ACTUAL ENGINEERING! Featuring a loop!
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- čas přidán 3. 09. 2020
- We're going back to school in this episode as a Real Civil Engineer explains how to climb the leader boards using actual engineering principles! We'll be shaving cost down whilst thinking about the actual forces acting on our structure and how best to design the bridge to cope. I've probably picked one of the more complicated levels to try and teach you this on as the level is a massive loop! Still, lessons are meant to be fun and interesting so I see no better way of getting my engineering knowledge across!
This may be used a guide for Poly Bridge 2 levels 3-15, 3-16 and 4-01.
If you enjoy the video please give it a like and subscribe to the Real Civil Engineer channel for notifications when I post future videos! Thanks!!
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LINKS:
PATREON: / realcivilengineer
MERCH: www.realcivilengineer.com
DISCORD: / discord
TIP ME: streamlabs.com/realcivilengin...
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About Poly Bridge 2:
Poly Bridge 2, the acclaimed bridge-building indie-hit is back! More levels, more features, more physics fun! New levels, new mechanics, a custom physics engine, workshop campaigns, and much more! Rediscover your engineering creativity with even more hours of puzzling fun!
#realcivilengineer #polybridge2 #engineering - Hry
Yeah butterfly effect is annoying, I hate whenever I put my spoon into my cereal and it causes my house to blow up.
Thank god for home insurance.
I wonder if you finished your cereal or not
Nah
Did your cereal survive tho?🍜🍳
I read "house" as "horse"
I SWEAR TO GOD if you finish those Frosty Flakes...
UPDATE:
I have since spoken to the producer of the game and can confirm this is a case of the butterfly effect. Changing anything in a level can cause other things to change as calculations etc will be run again and could have a slightly different outcome. This is the main problem with using computer simulations for real life situations, and is worth remembering when using any software to simulate something real.
Original:
I completely forgot about the level at the end of this video... someone please explain what the actual HELL was going on here? I was raging!! Haha
Chaos theory, the answer for all things. But more likely a variety in the games physics engine calculation causing a slightly different out come on another part of the bridge, even if it’s not attached to one another.
When you modified one bridge, it caused it to bend in a new way, changing the speed and position of every vehicle after driving across. This slight change in position caused a change in the amount of pressure at each point, breaking the bridge
The left bridge originally was barely holding together at like 99.9% stress, so when you reinforced the right bridge it sagged a little less, causing the limousine to stop a few pixels farther, which normally wouldn't be enough to cause a new break, but did because of how close it was originally. Basically, the limo stops in a different spot because of the right bridge having more support, causing the monster truck to hit is slightly differently and adding the 0.1% stress needed to break the left bridge.
Yeah, the level seems jank. When you are close to breaking, it started to become janky and I guess floating point became an issue.
That's my guess anyway
floating point precision issues. Nothing to see here, let's move on :D
This Poly Bridge episodes are giving me dangerous confidence to be an engineer and start building bridges with muscles
Well how else are you going to transport the materials?
@@CPSPD good one
The Infra series should show you how dangerous that confidence could be ...
@@CPSPD he said with muscles
@@ertugrulgazi1562 He said, "--how else--".
11:45 they did the backflip not just for shits and giggles but also to slow the car down so it didn't launch too high
he prob joking
Nope, definitely for shits and gigs.
Only for shits and gigs
it's poly bridge, the stress levels are changed by everything, whether it's connected or not.
Holistic bridge
That’s odd. Why is it like that?
@@zkassai.audio.2 because the code simply checks the stress of all pieces and displays the amount of stress on the most stressed piece
It doesn't bother to check whether any given piece is part of the "main" structure because that would be both presumptuous and complicated
I personally think it’s because.. well how do I explain it. The energy from one bridge gets like a weird shockwave type thingy over to the other one, the other bridge can’t handle it.. and down it goes. Pretty simple but probably wrong.
Quantum bridge
“Engineering can’t fix this” is a four word horror story.
14:47 The game operates on a floating-point system not a fixed-point system, so, when bridges are really finicky or close to breaking like yours was, there can be a butterfly effect from changing unrelated things.
If not that, the extra weight from the reinforced road coulve also made the right bend a bit less, changing the limo's placement a tiny bit, and affecting how the monster truck went over it.
Still better than pb1's rng when running the same solution twice, though!
Big brain
What they might of done is just make all random elements have a set seed and thus little changes could effect the random output for the next random element
I always parsed these unrelated changes as re-seeding the rng but I feel like some impossibly slight difference in the limo's position is a better explanation
@@luke-san7733 you are correct to my knowledge
@Luke-san It is a deterministic physics engine now, there is no actual rng, just calculations and butterfly effect.
RCE: Oh this piece broke, lets do a real life solution that would actually work.
Aliensrock: Oh that piece broke? DELETE IT.
I more like the 2nd option. But most of the time I end up deleting the entire bridge, that's when u know it's not gonna work
@ItzSpiro MUSCLES
real life solutions arent the way for climbing the leaderboard
QUINT REINFORCED STELL ROAD MUSCLE (using the new glitch) I CHOOSE YOU
@@legion999 NO! Mustn't like dangly road, mustn't like dangly road. It's not engineering, it's not engineering ! - RCE, 2020
I love how you go back and try to shave money off instead of just giving up once you’re under budget and complete the bridge
The editing for the fairy probably took longer than just building it out but its a nice effect
What are you talking about? The fairy was real. Did you perhaps mean summoning her?
11:45 he does the backflip to slow down otherwise he’d break the bridge when landing from that hop
I love how no one questions that his steam name is cheesy diablo.
"i will not do dangly road! it's not engineering!" I mean... Have you SEEN the golden gate bridge? that thing literally wobbles so much it can throw people off it if the winds are hard enough. it's the ultimate dangly road.
@@evanouk3297 Suspension bridges are "dangly roads".
The road flexes differently with the reinforced road and so the limousine stops at a slightly different point.
Usually it's nbd but on that bridge (without any shock absorbers) it's really important that the monster truck bounces perfectly.
"Damn it Jim I'm an engineer, not a programmer!"
RCE considering doing something pretty without a benefit? sounds like you've been around too many bilfs.😂
Who knew bilfs could be a bad influence?!
What’s a bilf?
@@breadleyloaf8528 MILF but BIFL for bridge.
@@Perceptious37 what the hell
@@breadleyloaf8528 It's in his previous episode. It's on the thumbnail.
1:24 spokes
Well done!
Thanks!
I think this video has the most profanity I've ever heard out of RCE, as an older member of the audience I'm all for it.
I think it might be cool if RCE went into minecraft (maybe creative mode) And made some bridges that theoretically would work irl.
And the flying machines he could make would be cool as well
Lol, your just vibing on a minecraft server, then you see a flying bridge come flying at you.
I meant like a flying car but sure a bridge would be cool too
Lol if he was to do so it should be in here
MC doesnt have physics
“Dangling road is something I’ll never do on my channel.” Oh just wait till your challenge level videos, past Matt. XD
Me: Plays polybridge
Also me: Stress level 99%
my eyes bled at 12:45 (It was funny tho)
That fairy edit got me 😂
I don't control how the magic works in this game, but I am grateful to the fairy for helping me out!
“Segmented, oooh, the word of the day I think” ahahahahahahaha
BTW, I liked your loop the loop explanation. It at least sounded like actual engineering! And it encouraged me to think about the force travelling along lines and you dividing the lines to reduce stress in a variety of ways. So good on ya! :-D
Thanks!
19:05 - "You've gotta force your way out of the birth canal at the end."
I laughed so hard! 🤣🤣🤣
Sanguine, pronounced like sang-win with the stress on the first syllable, has multiple meanings. One is hopeful, another is bloody. A brilliant name considering the rollercoaster of emotions you went through doing these levels.
when one needs a rhyme for penguin,
A semi-rhyme would be sanguine.
11:43 serious line rider energy. Pretty cool throwback
Wow! This one is one of my favorites so far...and I've been binging these vids for the last 2 days 🤣
1:15 I'm pretty sure the technical term for that shape is 'sliced pizza shape'.
The 2nd failed because poly bridge physics are actually still random. They're "Deterministic" (You'll always get the same result for the same bridge) but are still inherently random by default due to the nature of the game engine. You might be able to fix that by making miniscule changes to your bridge to make the game think its a 'new' bridge and re-roll the RNG
The reason the reinforced road made it collapse is because it's heavier than normal road. That made the right side bridge "sag" a tiny tiny bit, which changed how the limo parked on the left bridge (since it had to "drive up" and had to drive a longer distance) thus having the monster truck land differently when coming off the limo and crashing the bridge. (I'm pretty sure that's how it went?.... lmao)
my guess is that, the more pieces you have, the fewer decimal places it can simulate for each piece, which can turn out in your favour or not, depending on whether the number any given piece would've gotten is rounded down or up.
imagine something like 3.14159 turning into a 3.1416
@@windhelmguard5295 I doubt that's the case, since such optimization would save probably a few hundred bytes at most and it would be difficult or even impossible to implement in any widely used high level programming language
@@SophieJMore it would actually increase memory consumption, the code required to manage precision would use more memory than it saved.
The first bridge breaks because for some stupid reason the weight of the reinforced road makes the limo drive slightly faster/slower so that it stops a little further/shorter and so the monster truck hits it slightly different
That’s not the reason
Yeah the physics are weird and u have to accept it
yup
Welcome to chaos theory, where slightly different initial conditions lead to radically different results.
@@armyprivate4923 It is. It's an extreme case of the butterfly effect.
When in doubt muscle it out
I love ur videos they are so calming but also very entertaining. Perfect to watch before I go to sleep as it brings me much happiness and comfort. Thank you for the hard work sir.
I love how even though you pass the level but the bridge colapses your brain is like nah need to fix this so enjoyable to watch you figure stuff out
12:40 what the f
Easy friend, I'll finish the word for you:
Uck
Firetruck
I enjoy all kinds of magic. Pixy magic, lightning magic. My favourite of all though has to be editing magic :D. Thumbnail really hits me hard as I head off to school soon. Anyways, great vid, have a wonderfully wacky day, and take care out there.
Yeah it was unintentionally timely. I'm glad you're enjoying the magic, I am too! Have a good day pal!
I love that gag reflex noise u make when the bridge breaks
So glad I found your channel, love your stuff, keep it up!
Sanguine, /ˈsaŋɡwɪn/ optimistic or positive, especially in an apparently bad or difficult situation.
gulch
, /ɡʌltʃ/ A narrow and steep-sided ravine marking the course of a fast stream.
Sanguine also means blood-red, so it's Blood Gulch
Probably a Red vs Blue reference. Blood Gulch
Just discovered your channel and im a student aspiring to be an engineer. This is a really fun take on what being an engineer is like. I love it please continue making videos.
Thanks for the comment, and good luck for your future in engineering!
love that "i'm going to do sick flips and jumps, wait no, i'm an engineer. i'm going to do straight lines"
not sure how i found this channel but its brilliant to watch.
I like your hustle from 9.18 - 9.21 seconds. You almost tricked me! I was loving you at the start but after that I'm gutta keep an eye on you now! Haha all In good fun love the details in your videos really learn alot! ❤️
Not many noticed that, but I assure you it was just poor editing by me. I shaved it to be cheaper after and put that clip right next it, whoops!
Can't wait till you get to the newest content. Might be worth doing a weekly video on just the weekly challenge level.
Stumbled across ur channel, and i love it, u sir r very entertaining, keep it up brochacho
Rce: "I will never do a da gling road again"
Rce's video when he cheeses through all levels: I'm about to en this mans whole career.
Its interesting seeing RCE come into his own and start trying things with his edits that are a bit more unorthodox. Well done!
Any part in particular? I'm intrigued!
I think he means the fairy.
@@RealCivilEngineerGaming Yea just with the fairy and the other effects throughout. Things that add a bit of personality to the video. Besides your personality of course XD
Your narrative is relaxing and entertaining!
this man is so chill to watch
I'm out of quarantine tomorrow😊😊😊😊😊😊😊😊
Thanks for everyone who gave me tips on what to do
Just started watching your videos pretty cool!
The thing with wood muscles is, I think that in some cases the stress gets put on one side a lot more than the other, making it about as strong as wood, but with steel, all the strength is in the whole thing, so it stays.
For the bit where it randomly breaks this is called a butterfly effect. As reinforced Road is heavier than normal road the bridge will sag by a miniscule amount probably slightly changing the limos speed that makes the monster truck hit the limo differently and that's why you have your break. The reason why it happened with the muscle is because there was a slight change in balance.
Im loving your content
I LOL'd when the left bridge failed with the installation of the muscle.
(14:30) Real Software Engineer here: While the game uses stable simulation it uses IEEE 754 format for storing floating point numbers. This format is a good enough approximation, however neither + or * is associative, thus *a + (b + c)* may or may not equal to *(a + b) + c* . When you tweak any variable of your bridge, the material nodes might get processed in different order, resulting in sudden breakage even in disconnected parts of the bridge.
I'm hoping the devs will give me the actual answer! I'll suggest this though. But more importantly, how was the beet harvest this year?
@@RealCivilEngineerGaming There's more problems with the format: en.wikipedia.org/wiki/Floating-point_arithmetic#Accuracy_problems
so it can be a combination of any of these factors.
Harvest was twice as big as last year, a tradition in the Schrute family. We also had to double the number of Cylon guard bears to protect our fields because of the civil unrest.
I didnt realise how smart this guy was until he explained the anchor point stress thing mind blown
imagine my frustration before he finally uses springs at 3:50 😂
Love your editing
Thanks, it takes a while so these comments are really appreciated!!
11:12 THAT'S ALMOST EXACTLY WHAT I WAS THINKING AAAAA
15:05 basically since the bridge is different the limo had a different speed going across so the spot it stops is like 0.01 pixels different which randomizes the physics calculations.
Yeah can't wait for the challenge levels with his mindset of no dangly roads, that is gonna be interesting ;)
15:30 the reinforced road weighs more which causes the bridge to sag
polybridge is notorious for the butterfly effect
I watched this high asf and that fairy thing confused me so much i lost contact with reality
In the first level, I'm fairly sure you could have made the loop significantly shorter at the top, since you don't need to go higher than the checkpoints. This means you could probably get away with fewer road pieces, saving nodes, complexity, and weight on the whole structure, possibly allowing for further savings on the lower parts.
A slight change in how one bridge flexes alters how fast the limo is moving, which alters exactly where the limo comes to a stop, changing where the forces are introduced on the structure.
i'm so sad i saw now that i'm not subscribed to your channel but start to watch yours channel by when polly bridge 2 was launched. sorry i'm from brazil and i don't know english very well, but your videos is amazing
I think the specific issue in that level was there was a micro change in how the limo crossed the right-side bridge thus, the precise location it stopped on the left-side bridge was altered. So, when the monster truck ran over and back down the limo, it landed back on the bridge in a different pixel than before.
15:00 maybe its butterfly effect. U changed right bridge, limo drived over it and u affected the limo. Or randomizer depends on environment
I really liked the moment when you started explaining the muscle thing. Maybe you can go on sharing some of your engineering knowledge a little bit more often? :)
I came to make a smarmy comment about curve-y curves because of the loopty loop.......but I ended up learning how forces transfer through a muscle and being an engineer you have this scary ability to use our understanding of physics to make a bridge with the least amount of money possible........man.
Mission accomplished! Thanks for the comment!
14:45 I don't know for certain, but I'd guess that the extra weight of the reinforced road caused the right bridge to bend slightly differently, causing the limo to travel slightly differently, causing the limo to stop slightly differently, causing the monster truck to land differently, smashing the bridge. All that can really be done is you can either fiddle till it works, or over-design the bridge to make it super robust.
Sanguine is said like "sang" (past tense of sing) + "win" (victory) and comes from the Latin root for "blood". The same root shows up in words like exsaguinate (to drain of blood), but also is used to mean optimistic or bold in temperament (owing to its associations in the defunct medical theory of bodily humors). I think Sanguine Gulch might be a reference to Blood Gulch; a famous Halo map. Also, don't feel bad about saying hi to the gays at the end, it's nice to be included :)
As a mechanical engineer I must say. this looks fun
ARE YOU EXURB1A?
Do u have another YT Channel?
Exurb1a sounds exactly like you, humor, voice inflection, train of thought, everything. I love that channel btw, one of my favorites.
14:32 I have a theory as to why this happens, the centerpiece might be invincible but it might still transfer some force over to the other side, meaning when you reinforced the road, there was less give and it was more rigid.
Nah man, I had a more extreme version of this in the challenge version of this bridge with multiple monster trucks where I actually built some ramps and dips into the bridge so that the monster trucks could drive more easily over the cars.
Any change you make to the right bridge, be it a tangible change like shifting the peak of a ramp by a bit, or something seemingly irrelevant like changing some supports under the bridge, will affect the final position of the limo when it comes to a halt. This changes the point of impact of the monster truck that crashes into the bridge after driving over the limo. And that slight shift in point of impact can be the difference between having the force distributed or having all the force go straight down a single element... Or in the case of this video, it can be the difference between a 99.99% load and 100.01% load.
@@naphackDT I think I get it... thanks!
3:07 i learned this lesson a long time ago. If it breaks, just replace it with a spring
Edit or delete it necause you might not need it unless you know you need it.
As an civ eng student is his both educational and entertaining. Would like to have more concepts explained but it might be too nerd-ish
Things like changing other bridges affecting unconnected parts are usually because there's RNG in the game - the seed is generated by the structure of the bridge - you can change the outcome by placing a completely unrelated piece of wood unconnected to anything, because the RNG seed generated by the bridge will change.
My abo was gone ;-; I'm here since 1000 abos and I enjoy the videos so much, cause they so relaxing.
Sorry for bad english
The speed of the limo is changed bye the renforced road, so it's the placement of the limo that change in the first bridge
(i think, i never played this game)
Matt: "make this a little trussy "
Me: what kind of bussy is that? 🤔"
i want to see other designs as you finish
I think I thought of why the other bridge is affected. When the lemo goes across there may be a tiny bit of give in the bridge but when you make it stronger it changes where the lemo ends up by just enough that the monster truck breaks it at a weak point.
11:43 happy to see my bridge lol
When you added a muscle, the right bridge sagged slightly less, so the limo was going faster and therefore slid slightly further before it stopped, so the monster truck ran over it on a slightly different part of the bridge that was slightly weaker.
I have never played so Idk lol but love the videos I just subbed
Changing the right bridge could cause the limo going over it to slow down/speed up slightly, so that it arrives slightly later/earlier, so the monster truck hits it slightly further to the right/left. In other words, changes to the right bridge can be transmitted to the left bridge _through the limo_ because of timing effects.
Ok that last dangly bridge was kinda neat, and borderline engineerie
The game is not only factoring in forces from weight but horizontal forces both from the torque the cars tires pushing backwards on the road and with the monster truck crashing into the other car.
In the spring bridge the springs contracted on the left and expanded on the right because the force of the collision.
Your muscle was weaker for horizontal force.
I learn more from random CZcams videos than school and it’s not even close
Why do I get anxiety when he finishes his builds and test it 😂
I love ur vids
Sanguine
(Saen - Gwihn)
Root: related to blood
Def 1: one of the four humors in renaissance stage plays next to yellow bile, black bile, and phlegm.
Def 2 [Used Here]: a type of cold or stark tranquility; cathartic
When the right bridge holds better it flexes less (ie is more rigid) under the weight of the limo, which affects the speed of the limo and how far it gets before stopping.
Remember, Poly Bridge likely uses seeds for the physics engine. It looks like the seed that is used is generated based on the bridge you build. I haven't checked for myself if the game uses a seed but everything I've seen so far suggests that it does. If not, it is probably what someone else suggested. Changes to one part of the bridge can change the location on which a car stops somewhere further along.
... First... Your commentary is so bloody hilarious, it's Killin me! Keep it up! Second.... I dont want to generalize all British CZcamsrs, but you sound exactly like one of my other favorite brit YT-bers named Exurb1a... Have u ever heard of him.
Even your sense of humor and quippie train of thought is so similar. Have you ever been mistaken for him?... If I am mistaken, that is?
I'd love to know,
-JAY from ATLANTA
Had quite a few comments on this actually haha, I'd never heard if him until commenters here told me, but his stuff is really great so thanks for the compliment!
I'm wondering (and someone who knows the game better can correct me if this speculation is wrong) if the game treats certain pieces as unbreakable structure where force is transferred. If the 2 tier section of road in the middle is transferring some small amount of force, adding the extra weight from the reinforced road, or the extra stiffness afforded by the muscle could cause the forces in the left side to increase.
Also, a few things to consider: since game physics systems need to do calculations in real time, they tend to be much less precise than proper simulations. This means that since they are using floating point numbers you can run into precision errors. Remember, a floating point number is incapable of representing certain values entirely, which can cause errors that will propagate through the calculations. It's possible that by changing or adding nodes you are changing the calculation itself, which changes how an error propagates through the calculation.
Hey man i think that the black car is not stopping at the same point because since the stress levels are changed when you reinforce the first bridge, its geometry bend very slightly differently each time, thus affecting the travel distance or speed of the first car, and that affect the collision with the truck somehow. But that's just my guess ! Enjoying your videos very much, thank you 🙃
you are right on th3 monster truck brige, it is just some rng, it was worse in pb 1