Simulating a Chainsaw (Attempt 1) - Engine Simulator Devlog 5

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In this video, I continue working on Engine Simulator, adding more detail to the engine model and creating a simple application to edit engines in real-time while they're still running.
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Timeline
00:00 - Intro and Master Mechanics
00:27 - Squarespace
01:18 - The Reference Engine
02:47 - The Simulation
05:40 - Initial Results
07:30 - Bar and Chain
09:34 - Fixing the Idle
11:01 - Carburetor
12:06 - Final Result
14:38 - Conclusions
#physics #simulation #gamedev
FTC Disclaimer: This video was sponsored by Squarespace.
Thanks for watching!

[@AngeTheGreat]

EDIT - To those suggesting extremely simplistic "fixes" to this simulation: I appreciate the advice but the simulation isn't as simple as you're making it out to be. Trust me, the first thing I tried is "randomizing" the combustion events. It really doesn't work. I was going to include a clip demonstrating this but I cut it due to time limitations. The probabilistic model that I'm using IS random already. The periodic firing is due to other resonances in the engine and periodic variations in AFR and exhaust gas dilution. This oscillation is very complex and not trivial to adjust manually as it's an emergent physical phenomenon and not directly controlled by RNG. Throwing more RNG at the problem does not fix it in the way that you'd expect. I do have functioning ears and as I stated in the video, the end result is not a perfect recreation of the reference. My goal is to get videos out to you guys consistently which means that every video will show this project in an incomplete state. Some have suggested that this more recent work is somehow "worse" than the original Engine Simulator. I suggest rewatching those videos and realistically assessing how "true to life" those sounds actually are. Single cylinder engines are also significantly more challenging to generate convincing audio for. If I were to reimplement the same simulation in this video using the significantly less sophisticated fluid simulation from ES2D, I think you'd change your mind pretty quickly about how much better that software supposedly was. ORIGINAL COMMENT: I would have wanted to get the idle sounding closer to the real thing but the combustion model just isn't advanced enough yet to deal with the complex behavior of 2-strokes at idle. This definitely isn't the end of the chainsaw simulation journey though and I'll revisit this soon. Hope you guys enjoyed the video anyway and I'll see you all next time!

[@RachidGot-md1th]

Make a engine simulator for mobile

[@frodo4087]

@@RachidGot-md1th good luck having a good enough phone

[@heavygaming6596]

​@@RachidGot-md1thLow IQ comment

[@manitoba-op4jx]

@@frodo4087for the cost of a phone that could barely run this he could build a kick-ass last gen gaming pc

[@AX67488]

Will there be engine simulator for macos or other devices?

[@feschber]

I always think "Wow this sounds near perfect" and then Ange comes along with the "now this does not sound quite right", proceeding to make it even better.

[@youngbloodbear9662]

Honestly imo it got much farther away at the end compared to that moment

[@kezif]

You don't need to make game realistic to make it good. Quite opposite is true, highly stylized are often threated as timeless and realistic one out of the loop in 2 years

[@roadsidegarage69]

@@kezif bot ass response this is a simulator not a game you dummy

[@josephclemmons5234]

​@@kezifinteresting theory but this isnt a game

[@Thetankracer]

​@kezif My guy, this is a simulation. Being as realistic as possible is its entire point in life

[@user-ib1bz4bh3g]

This sounds really good. I think that in idle there are also vibrations of the entire chainsaw and its components that contribute to the overall sound. So tuning and improving the fluid sim might not be enough to achieve the perfect idle sound.

[@morgan0]

yea adding something that simulated physical resonances of the body of the chainsaw and motor would probably help

[@WarttHog]

Exactly. At idle they take and spit and pop like they're falling apart. TBH an idling chainsaw scares me more than a full throttle one haha! No idea how you'd simulate that though without the model becoming ridiculously complicated. To make matters worse, I bet the pops of the ignitions following a misfire are shooting vortices out of the exhaust that are reverberating off of the environment. Not an easy problem but I admire your courage to attempt this thing!

[@user2C47]

​@@WarttHogEnvironmental reverb is not something the engine sim needs to handle. That's the game engine's job.

[@matejlieskovsky9625]

​@@user2C47yeah, but good luck having the game engine handle air vortices.

[@WarttHog]

@@user2C47 I was talking about something more violent than just a reverb effect on the waveform. I was talking about the impacts of vortices making stuff rattle. But that's probably dumb because: 1. You're right that it's certainly beyond the ICE part of the submission. 2. I'm probably sensationalising and that's probably not how reality actually works. 3. I actually don't know what I'm talking about and don't quite understand why people upvoted me, lol.

[@rocketplane8862]

Sounding good! With model airplane two-strokes, we call the misfiring at low speed "four-stroking" because it basically starts to sound like a four-stroke engine, firing on every other stroke as the AFR gets into the right window. I also think part of your problem is that your simulated muffler isn't muffling very well because of the ideal nature of the quasi-1D simulation. You could probably get some milage out of a "minor loss" model, which adds some pressure drop for things like sudden corners or pipe elbows. Don't let the name "minor loss" fool you, for a very short runner like that box muffler, the minor losses can easily outweigh the major (wall friction) losses. An easy way to test the corner dump case would be to arbitrarily inflate the friction factor in a very short length of pipe that expands from the initial cross section to the final one.

[@Alfred-Neuman]

Yeah, this should be pretty easy to do. Just one or two more functions with a few variables mixed with some operations, nothing too complicated... :P

[@roderik1990]

Also wondering if maybe some of the transfer matrix methods might be applicable here for modeling that muffler.

[@ConeDodger240]

This is certainly the most I have ever understood about how 2 stroke engines work. This is also the most I've ever understood about how 2 stroke engines never want to work.

[@teknikal_domain]

2-stroke engines are the helicopters of engines. We have this thing that's stupidly complex and needs everything to go just right... And flipped it so instead of trying to correct itself when something is unbalanced it just turns inside out and explodes Engines themselves are already kinda precision machines, and 2-stroke engines kinda openly mock that

[@Stork2204]

Great job with two-strokes, you never disappoint. Super excited for carburators in the future

[@selachian]

Not as insanely true-to-life accurate as some of your car simulations, but still very impressive and nothing I could even dream of being able to do.

[@AngeTheGreat]

You can get away with a lot more shenanigans with car engines since there are more cylinders and more places to "hide" so-to-speak. 1 cylinder engines and especially 2-stroke engines are very unforgiving which is why I'm focusing on them right now to refine the simulation as much as possible

[@PlasticCogLiquid]

I feel like all your work is going to change video games forever when sound simulation starts getting procedural. Do guitar strings next :D

[@gwentarinokripperinolkjdsf683]

Aren't guitar strings a well researched and solved problem

[@hunterlang578]

@@gwentarinokripperinolkjdsf683 Yeah, stringed instruments in general have been very well understood for hundreds of years

[@zekeaffy9647]

There are still some engine types havent simulated sound wise, like jet engines and turbo fan engines. It would be cool to have a Rolls Royce trent 800 900 to roar and it is simulated.

[@PlasticCogLiquid]

@@gwentarinokripperinolkjdsf683 Still have yet to play any kind of synth that does guitar strings accurately, so I'd say no.

[@Alex_1652]

Strings dosnt really relate to fluid simulations, its completely different subject.

[@MetroidChild]

A major PITA with carburetors is the fact fuel doesn't like to get aerosolized when gas speeds are low (such as when idling), this means that fuel droplets will unpredictably pool up on surfaces before evaporating, leading to a more unstable AF ratio, which also contributes to the unstable idling. These problems tend to go away at higher RPMs due to higher gas speeds and from heat soak during load which helps to evaporate the fuel. Aim for a 0.8-0.9 lambda!

[@TestECull]

Yep. For most 2-cycle engines it sounds like tehy're just straight up not firing on occasion. Where they get that 'ring a ding'. My K&B 61 is a very VERY strong example of this(and I have video of it on my channel!).

[@Donn29]

Wall wetting when the walls are the crank case must have a lot of inertia/delay/whatever between big changes in airflow.

[@233kosta]

... And now we're in surface tension territory 😂 This stuff is a pain when I'm dealing with just regular water, and there are quite a few well-documented models for that stuff. Fuel/oil mix is probably going to require a bunch of backyard lab measurements just to get started! Way I see it, it's not happening. Not on this scale, not in this sim. That's the sort of thing you'd pre-compute a table for (or some coefficients for a polynomial) before running the real time sim, and hope it's close enough for most conditions.

[@233kosta]

​@@TestECullYeh, they pretty much aren't. The pops are the firing events, the rest is just free spin. There's not enough fuel there to light the charge at all.

[@233kosta]

​@@Donn29With the carb tuned for steady state under power, this stuff would have a minor effect. Mostly it would enrich the mixture after the engine has already spun up, which would be handy for keeping it a little cooler.

[@ole3620]

honestly, this sounds better than every other game developers made their chainsaw.

[@ZerpsT]

Always insane what you're able to achieve by yourself

[@monad_tcp]

its amazing what you can do when you only use math as a "library" and actually program everything yourself from the ground up

[@crottemole]

The idle from the simulation is actually very similar to how an old single 250cc snowmobile would sound for a few seconds after returning to idle from a rev!

[@steeliewheelies]

Carburetor simulator would be very valuable to a lot of people, me included

[@ncopp4358]

Do people really struggle this much with carbs? I picked up how to dial one fairly quickly once you've figured out what everything does.

[@steeliewheelies]

@@ncopp4358 who said anything about struggle? That’s exactly what a simulator would be useful for though, visualizing the concepts and understanding how each part works together. Me personally I would just have a lot of fun designing and simulating carburetors in general. Combined with engine simulator it would make jet calculation a breeze, that’s for sure

[@MichaelSmith-on1ig]

Sounds almost perfect! I'd say it still has a "plastic quality" to it, like it's modelled from plastic. You might want to introduce some rattling and grinding from the saw blade and other mechanical components. Also you should emphasize the characteristic tinny sound of the two stroke engine. With a convolution reverb I'd think.

[@erkinalp]

plastic engines exist irl

[@jamiesamyn3988]

@@erkinalp yea.... hyundais

[@yoloboogie3674]

@@jamiesamyn3988RACIST

[@Map71Vette]

I think this is almost kind of like the uncanny valley, just in sound form instead of visual. It's definitely very recognizable as a 2 stroke engine, but hard to put your finger on exactly what if off about it. Generically speaking I guess you'd just call it "synthetic" sounding, which is exactly what it is, but it's hard to express exactly what that means. Regardless this is super cool and I've enjoyed following along and am eager to see where it ends up. I can't imagine the amount of time is has taken to get here for just a pet project, kudos!

[@Beatsbasteln]

You officially revolutionized the saw oscillator!

[@flameendcyborgguy883]

To be honest the fact that BeamNG supports you and your project is both surprising and predictable. I mean, this is something right up their alley, and fitting it into the game would be very much apropos.

[@joe328i]

Wow, this is really impressive. Sure, the idle is a little off but the rest is pretty much on point. Qhat got me the most was the reoccurring of combustion when the AFR gets into the right window after the engine revs down. Keep up the great work!

[@stratos2]

Very nice! For two strokes it's also important to note that many of them wouldn't, or would only barely run without well tuned resonator exhaust. It actually uses the exhaust wave bouncing off the end of the exhaust, then back again off the cylinder to draw a vacuum right as the exhaust port opens, drawing the burnt combustion products out of the cylinder.

[@2Stroke250]

that is literally the exact opposite of that expansion chambers do, look it up. also almost literally any 2 stroke will run without one, and most of modern 2 strokes have Schnurle transfer port design where the transfers point towards the intake side to direct fuel away from the exhaust to reduce negative impacts of not having a expansion chamber.

[@demariultraastra864]

This would have been inconceivable a few years ago even if it was just this one engine, let alone being able to make literally any engine within a few hours! Every time you upload it completely blows me away!

[@Majima_Nowhere]

Your videos always start with "eh it sounds too perfect, don't know how he could improve it though" and end with "are you sure this isn't just a real sound sample?"

[@fillman86]

wow what phenomenal work you've done!! the sound's realism seems to have taken a huge leap up again!! it's also presented in a way that a layman like myself can comprehend!! Loved every second! I'll definitely be wish listing this

[@herrherher2502]

Are we gonna see a few beam mods with his Sounds

[@TlalocTemporal]

​@@herrherher2502-- I think BeamNG stock vehicles are going to implement this at some point.

[@fillman86]

@@herrherher2502 not yet, I hear he's planning to possibly make a beamng exporter though as for beamng implementing this, I doubt it'll be to this level, but they have talked about making engine simulation in beamng a lot more realistic

[@nerd_nato564]

​@@fillman86Considering how Beamng are actually supporting him now, I wouldn't be surprised to see it, even if it only runs when you modify part of the engine and records the sound.

[@fillman86]

@@nerd_nato564 lol I don't think beamng will ever run it, because their game's performance already sucks, and this would not help that

[@thejo6331]

that's pretty damn good!!! far-and-away the best 2-stroke sim I've ever seen. Arguably way harder than just sticking with 4-strokes, but this introduces a lot of the complexity needed to replicate a realistic lumpy idle or other inconsistencies in an engine's sound. amazing work, friend!

[@peatral]

I have absolutely zero knowledge about engines and anything related to it, but I still keep finding myself fascinated by this project.

[@RamenPoweredShitFactory]

Ended up sounding remarkably similar when it was done. Very cool.

[@VoxelMusic]

Your engines get more and more realistic with every video. Its amazing how optimised you've got the fluid sims. You could make bank selling ultra realistic instrument VST's once this engine simulator is done.

[@dittilio]

What I find most remarkable is how it could be moderately straightforward to reverse this and turn it into an engine diagnostics and tuning tool. Dial in the parameters of the engine in question, hook up to an OBD or other ECU style feedback, and see an immediate before and after effect of tuning something on the engine without having to actually do it. Simulation of a repair/upgrade to prioritise parts and fixes.

[@_wyans]

Can’t wait to start recording audio samples, it keeps sounding better and better. Great work!

[@NFBartos]

Ange, you blow my mind every time you release a video. You're an absolute legend. The fact that changing the fueling in your simulation changed it's character so much (towards reality) is a testament to how well you've modeled everything, it's just incredible. Supporting you is the best money I've ever spent.

[@c0mplex564]

Can’t wait to get my hands on ES3D. I’m gonna have a field day with it.

[@102ndsmirnov7]

I like how I came into this video thinking I'd see cool progress on the engine sim and I did. What I didn't expect is that I'd also learn about how a chainsaw functions, awesome video as always!

[@AnAbsolutelyRandomGuy]

Wow. Its insane how you do this stuff

[@einglis]

I can't get my actual chainsaw to run, and then you come along with this masterpiece to compound my ineptitude! Great work :)

[@BrassRoots64]

Amazing video, Ange! I never could've guessed such realistic sounds were possible using only fluid and load simulation. It's amazing how much of the characteristic sounds doesn't just come from clicking, loose fits, etc. and how much of it comes from the combustion process alone. Thanks for posting!

[@Nirossen]

I love seeing your channel evolve

[@EpicLPChannel]

Your visuals are always top notch.

[@everettstormy]

Its awsome to me that your a hands on person. Im facinated by this stuff becuase i work on it constantly and know little about computers. That fact that you are briliant with computers and a working man is commendable.

[@ScarlettStunningSpace]

I love what you've been doing. Slow and steady wins the race

[@kasperwinterhag]

The full throttle cutting sound is really good!

[@pindab0ter]

Always looking forward to the next video!

[@gerbil7771]

You are a truly talented programmer, amazing work.

[@maxnewdf]

This is getting so much more awesome by the second

[@cooperthompson4850]

Damn this is so cool. I love small engines

[@mikeraphone7868]

Every video you release is so impressive and inspiring, this is exactly the kind of thing I like to see or want to work on myself. I love audio and I love low-level physically based simulation. I can't wait for the day when a system like this can be used to realistically model engine sound in videogames or simulators when changing aspects of an engine.

[@a52productions]

It's so satisfying hearing the engine get more and more accurate and complex as more features are added. I love this stuff so much!!

[@modus_ponens]

Got to say this was the most impressive engine simulator sound so far! Hats off

[@IstasPumaNevada]

I always love seeing/hearing the updates on this project. Also Steam Engine DLC let's go! :D

[@NicolasPicklelas]

Sounds great!

[@feschber]

My expectations are always blown out of proportion! It sounds so realistic!

[@ProfessionalToffee]

One again Ange, you've knocked it out of the park. :)

[@sakenitro]

The final product is going to be insane! IMO, one of the most impressive pieces of software made in ages. Great job man!

[@harleymatthews761]

I am really impressed; it sounds very, very similar and impressive. I love your work man. Keep it up!

[@PyroNicampt]

Probably a good chunk of what's missing is the mechanical sounds from imperfection in construction and play in the components, what's coming through with just the fluid sim though is absolutely stellar!

[@thomb629]

Very interesting at 14:07 when the engine briefly goes into four-stroke mode (only every second revolution ignites). A very familiar sound to anyone running nitromethane RC model engines. Happens when the engine runs too rich. When breaking in an engine, it is run like that intentionally. Cool that the simulation produces this effect. Thanks for another enjoyable video!

[@cmdr_scotty]

excited to see what you come up with for simulating fuel induction (carbureted, and such). I'm really looking forward to the finished version of your engine simulator and to use it to simulate changes on my project car's engine! one thing that would be neat to see (probably WAY down the line of development) is to simulate vacuum ignition advance like what is used on older cars that do not have a computer controlled ignition system.

[@kaloyannikolov6849]

Amazing work, Ange! As you said yourself, it may not be perfect, but the off-throttle sounds are ABSOLUTELY spot-on! Very interested to see what the future of the project holds 🤞

[@jvoyager1]

Dude, I love your work so much!

[@danielcarroll6303]

Bonkers, truly you have a firm grip on reality and how it works.

[@AmeliaBadeliaForever]

This video helped drive home some concepts I intuitively understood by listening to engines run and doing maintenance / troubleshooting. Thank you. Currently binge watching your channel from the beginning, just stumbled in here

[@bunger8658]

once again you've made something I never knew I needed in my life. Very cool project once again!

[@christopherhargreaves1979]

Sounds amazing. Adding a centrifugal clutch makes me hope you'll look at snowmobile two strokes and their CVTs.

[@VitriolicThunder]

This channel makes me happy.

[@JakeABee]

You did a great job recreating the sound it’s so close!!!

[@nibbaggggg]

Instant click. These videos are the most interesting thing on internet rigth now❤❤

[@bruno5601]

BEAUTIFUL! Love it. I was thinking that another thing that would probably affect the sound would be some effect the plate. It should act like an antenna, filtering the sound at resonance frequencies and also with some direction.

[@stamdar1]

Love this project, been following since day1 and always bring you up at the car hacking village at DEFCON. Keep up the great work!

[@andreasandersson5972]

Amazing stuff! Think of the carburettor only has 2 hard settings for fuel, low speed and highspeed. That is the reason why it always sounds in-perfect (wich sounds perfect to me). They also have other functions such as full throttle fuel boost to make it response better at full throttle. Good luck and the thing I would look forward the most is the induction sound in na tuned 4cylinder with weber carburettors or ITB injection systems!

[@tuopi27]

im so incredibly impressed that this man has such a mastery of fluid physics to accurately *_simulate sound_*

[@ATrustInThrust]

This sounds so good.

[@michaelbauers8800]

That is so cool watching the fluid sim

[@nathanielostrowski2437]

So close my man! Would love to hear a 250 two stroke video. Dirt bike style. Found your channel yesterday and have been binge watching. Absolutely love it!

[@teamruddy611]

9:53 The simulation is so perfect that it doesn't capture reality, which is usually full of chaos and disorder, with a few pockets of order and predictability here and there.

[@devakadex9588]

Man im so excited to see engines wirh more cylinders to see how they sound

[@jamiesamyn3988]

as someone in the tree business this makes me too happy to hear be recreated so perfect

[@ben196shorts]

so basically, for almost a year now, ive been building a mini bike using a 127cc 2 stroke single cylinder engine. when we first got the engine running, which was its first start in well over 10 years, we forgot about the clutch housing. the engine had a centrifugal clutch, then the clutch blew up and everything went flying, no one was hurt, but that was pretty funny. also i love your simulation, ive had it on my laptop for some time and i love it. keep up the great work!

[@bytesandbikes]

Sounds really great! 😊 The dynamics of airflow in 2 strokes is really complex. There is one more effect I can think of - wetting. You get poor vaporisation in the carb, it ends up splattering in the crank case and evaporating later, giving a very pulse rich idle.

[@TheCherry1994]

This is just impressive and very much fascinating,

[@Maccaroney]

Heckin cool. Love it.

[@Dysiode]

2 minutes ago!! Love the gradual build up of complexity. Helps demonstrate the many hours of coding you saved us from :) I think the simulation is still a bit too clean/consistent, the pops at idle are more rhythmic than the real engine, but overall when not comparing them directly it's definitely easy to imagine the simulation as a chainsaw!

[@onefastgmc]

I could spend hours playing with this... Super cool!

[@Atezian]

It sounds really good when letting go of the throttle

[@LuxGamer16]

Wow, there goes a lot of math into this. Really mindblowing to see this.

[@karelpgbr]

Man I cannot wait for this to be a little more polished and easier to modify, I want to try all kinds of goofy things with engines Love your project Mr Great 10:42, I started to smell hot gas and fresh wood when that sound played

[@steeliewheelies]

Chainsaw simulator sounds great man

[@felipediiorio9344]

broo this sounds so good, my first bike was a 2 stroke and i can hear she from this vid lmao, u goin to change the sound generation for mostly every digital source like videogames

[@drrrrockzo]

Sounds pretty amazing, i think the "missing element" is the jingle jangle from tolerance/backlash/slop in the clutch-chain assembly.

[@parkourpotato6066]

i've never dabbled in small engines but seeing how a chainsaw works was really cool, the centrifugal clutch makes so much sense

[@CARPAudio]

This is very very awesome! I think you're getting very close to what is actually possible when recreating the actual soundsource fundementals of a chainsaw. Recreating the accoustics should take it to the next level tho. Are u considering using Impuls Response convolution? Convoluting different parts of the chainsaw could help. Like a convoluted plate reverb recreating the Impuls Response of a metal plate. This is not environmental so you're basically still at the source level.

[@MrSaemichlaus]

Amazing! Engine sound definitely depends on the load, not just because of binding in a chainsaw. If you rev a car at a stoplight it just doesn't sound the same as when you pull away.

[@tejdz1337]

thats so fuckin sick that you got the uneven firing of the 2 stroke so accurate

[@cosmo8743]

damn bro thats pretty good. it might not be perfect but its damn close

[@32BitJunkie]

The engine sounds like it's saying the word "vroom". That's such a good onomatopoeia

[@stupid_ahh93]

This man is cooking, and he's doing it perfectly

[@Oblithian]

The base tone often seems oddly high pitched but the simulation itself is always impressive.

[@jamesmccrory6921]

Always impressed by your dedication to simulate complex systems! I'm glad you took on the task of a chainsaw, and you obviously already have a lot of experience with them. As an ex workshop technician at STIHL, I wanted to suggest some things that might get you closer to the idling sound; 1. Spacing between exhaust and transfer port This is a critical distance which looks to be a bit too close on your model. Ideally the transfer occurs just before the piston reaches bottom of travel. It is normal to have exhaust gasses in the transfer port, and STIHL engines are actually designed this way to delay fuel/air mix being pushed straight out of the exhaust. 2. Throttle and fuel mix At idle, there is a small opening on the carburettor butterfly that allows air through, I'm sure you measured this gap already. Fuel/air tends to be mixed on the richer side during idle. This is intended to keep good lubrication but also creates higher levels of incomplete combustion. On some models there is a technology called 2-mix which has an additional transfer port for fresh air. The fresh air buffers the fuel mix from exhaust gasses to make for more complete combustion.

[@anthonysteinerv]

Man you are truly the goat.

[@DubUltra]

great video

[@zackshick11]

this is pretty goddamn impressive

[@billert_bone5663]

Good job

[@Feltare]

As a rocket enthusiast, i can only hope that eventually this can simulate rocket engines. That would be a dream come true for this. Amazing work!

[@bene5431]

Should be doable already