Physics of JellyCar: Soft Body Physics Explained

[@llamaliver448]

I was telling my friends about playing Jelly Car when I was little. Then I just happened to see Worlds being made and releasing in A MONTH! My childhood is back. Thank you!!!

[@rydergolde3169]

literally same! I haven't played the original Jelly Car or Jelly Car 2 in AGES but I vaguely remember the dumb little cars I drew in JC2 because I was a goof also remember hearing a lot of that "wah-wahh" from falling or being stretched too much

[@rko2016]

you said you wouldn't get into technical details of how to do these things, but i would actually LOVE an in depth explanation video, i love learning the coding side of simulation and IMO it's the most difficult subject to find guides on besides topology. (as a layman)

[@rythegy4419]

This is an amazing video. You explain everything so well without getting crazy technical. Can't wait to play the game

[@Tim_The_Dim]

Jelly car was one of my childhood games, I loved how fun and cute it was Thanks for reminding how great a game it was!

[@PavoneSoftworks]

This is so cool! I used to play JellyCar 2 on Wii. Hard to believe that was over a decade ago. Back when I had no clue how game development worked.

[@Show-wi7cw]

ßóf5

[@TeslaPixel]

I remember playing the original jellycar on my iPod as a child over a decade ago, great to see you're still passionate about it. Great game and great video.

[@WalaberEntertainment]

Yay! let me know what you think of the new one :)

[@Chickenkeeper]

Thanks for making this video, it's exactly what I was hoping for! I'd been working on a little softbody toy but was having trouble with buckling. Your solution to that is just what I'm after, and you also showed that I was on the right track with my collisions, which makes me feel much more confident about that. I'll definitely be recommending this to anyone working on similar projects 🙌

[@kosherre6243]

I like hearing the first 2 seconds; "the Jelly Car" sounds sooo phonetic

[@owenharrison8012]

This might be my favorite video on youtube right now. Im trying to make a softbody game of my own, this is huge inspiration and nostalgia!

[@Ethanthegrand]

I used to play Jelly Car 3 on my IPad 2. It was incredibly fun and very unique. So happy to see a modern sequel!

[@memetech-]

2:20 happens all the time, I find it really funny especially since real jelly does this too

[@naturestuf9148]

It's rare to see such an original game full of unique 2d platforming ideas. Thank you for sharing how the game is made!

[@ronaldiplodicus]

Looking at anything Jelly Car related is giving me such insane nostalgia- I legit thought this game was a dream, I need to go play it right now.

[@ittixen]

The perfect fusion of *Gish* and *Elasto Mania*

[@dfs-comedy]

That was really fascinating. I'm a programmer, but not a gamer or a game programmer, and I found this explanation really compelling.

[@Productions7777]

Can't imagine all the maths behind this, beautiful result

[@TMinusRecords]

You made the jelly car games!!! They were amazing

[@mattiasfagerlund]

I love this, I had never considered the frame idea to maintain shapes! Brilliant ideas and brilliant presentation! How do you handle friction? I've been looking at verlet integration, and it turns out friction is quite difficult. Everything skates around...

[@maxmultibamboo891]

I would imagine you make them both have a friction constant, calculate that as if It is a square on a flat plane, then you distribute the forces based on the ratio of the point’s average masses for that line.

[@JavierAlfonsoBellotadeFrutos]

As he said in other answers "I sort of gloss over it in the video, but the step where new velocities are calculated for the points in the collision step does in fact take friction into account. In my case I define materials, and then define material pairs that set the friction for that pair.".

[@LocalBosnian-99]

NO FUCKING WAY I THOUGHT THAT GAME WAS SOME KIND OF FEVER DREAM???? HOLY SHIT MAN THANK YOU FOR MAKEING A VIDEO OF IT IVE BEEN SEARCHING FOR IT FOR AGES!!!

[@qdeanc]

This is so informative and inspiring! I've been learning game dev for 7 years. My ideas are overly ambitious, and I've realized I must build a custom physics engine to achieve my goals. Seeing how you invented one of my favorite mobile games is incredible. How you solved problems with creative solutions, cleverly show/explain the complex algorithms, and managed to stay humble through it all...I admire you 😤

[@whytophat]

my brain expanded 5 times while wathing this.

[@SuperMaDBrothers]

Really awesome video. Extremely rare to find someone who actually cares that the audience understands what they’re saying. Awesome visuals and explanations. Not overcomplicated at all. But you never talk about FRICTION!!!!! Pretty sure you left this out, I can’t imagine the wheels working the way they do without it

[@foobars3816]

Oh wow, this is actaully incredible. I had never heard of this game before, but I loved your super clear explination of how the game works. I hope you have huge success!

[@Guarrow]

I remember playing this when I was younger, it was already one of my favorite flash games. I've been waiting Worlds ever since !! I loved the demo, can't wait to play that

[@h4tt3n]

Very inspiring! You are really good at explaining the principles behind the game physics without going into too much detail about the math or code. I'm having a blast creating my own soft body physics engine. If anyone wants to implement the shape matching algorithm, there is a really good in-depth explanation on the lisyarus blog, in the post "Making a 2D soft-body physics engine".

[@tyelork]

Really neat video! As a fellow developer myself I always love seeing cool videos showing techniques and logic other developers use and have used for their own projects. Some of these ideas are incredibly ingenious for fast softbody simulations, and could obviously be expanded to 3d as well, at the cost of extra calculations.

[@speedntktzlastname2182]

This game gave my kids so much joy and just hearing the sound effects or music makes them laugh and smile. Now they are young adults pursuing education and careers.

[@Nebuch]

JellyCar Worlds is a safe space for me among fun-physics platformers. See how it works is fascinating. Developing games myself and usually find "zen" in fun-physics ^_^

[@MrSaemichlaus]

That's amazing. So many things here that I think I could pull off with some patience. The soft body physics make the game much less predictable, which leaves little opportunity for getting bored.

[@bejoscha]

This is the video I would have needed all the years back when I was playing with exactly this kind of physics based doodles (using Processing). It is exactly the right amount of explanation with great visual cueing to give me back the itch of "I want to try this". I've never seen the actual game until now, btw. Need to check it out. Thanks for the video.

[@Cameo221]

Shape matching is quite popular with certain types of games. They will use it to make a ragdoll attempt to match an animated character for example.

[@iangsinclair]

Great game, great breakdown. Did wonder : how do you approach friction between your shapes? Would be cool to see your thinking there too. :)

[@professeurredstone2134]

How do you manage to simulate the friction between two platform or the wheel and the ground, to push the car in one direction ? (very good explanation btw)

[@WalaberEntertainment]

I sort of gloss over it in the video, but the step where new velocities are calculated for the points in the collision step does in fact take friction into account. In my case I define materials, and then define material pairs that set the friction for that pair.

[@JKa244]

It's interesting that one of the failure cases for collision detection is actually a half-ass simulation of impalement. Thin object passes through broad side of another object if it moves quickly enough. Then collision still occurs keeping it in place

[@sear9993]

I remember sitting in 2nd grade computer lab playing belly truck and my friend asked me what I was playing. This was one of my favorite games from my childhood.

[@sendheIp]

Have you encountered situations where the closest point is not correctly identified on the intended edge? For instance, if a point falls from above and penetrates a square near a corner, the closest point may incorrectly be calculated on the side edge instead of the top edge.

[@WalaberEntertainment]

Yes I have. I do have some code that tries to prefer finding points whose normal points “away” from the penetrating point’s normal, but it’s not perfect.

[@AlmondAxis987]

As a beginner programmer, this helped so much for my physics engine I made! And the collision detection was also fairly simple unlike SAT algorithm.... Huge Thanks!

[@gmdrandom6287]

SAT imo is simpler for collision resolution though

[@BuyMyBeard]

Wow! This game was part of my childhood, and now I am an amateur gamedev taking interest in computer physics simulations. This video was super insightful! 😊

[@karlmin8471]

I'm a physics student and thanks for your sharing. It's very helpful for us to understand rigidbody physics.

[@How2Bboss]

I remember playing Jelly Car on my Wii a long time ago. I had no clue that there was a new game! I love physics simulations; they're so fun. It would also be nice if you added the macOS version on Steam.

[@noThankyou-g5c]

i cant believe i never hear ppl reminisce about this game. when I was a kid this was basically the only game you could get on the original iphone/ipod touch! everything else was like “beer glass simulator”. And this was back when the biggest mobile games were real games and not just addictive feed back loops that manipulated you into watching ads

[@Gxaps]

I used to play this game as a kid. Nowadays, I do game modding, and I’m totally gonna use this for modding purposes!

[@fanchink]

I came here thanks to Parking Garage Rally Circuit, and I stayed for the teaching. Offering fun and knowledge: you have my subscription and all my respect 🙏

[@PhiLudo]

absolute amazing video. i love how you used the debugs to visually explain everything. you even helped me with an solution to my rope physics.

[@FathomRaven]

This is a really cool video, Jelly Car is so nostalgic for me, being able to see how it works is awesome

[@fntthesmth423]

I for one deserately want a video from the sound designer of jelly car because some guy standing right behind my shoulder softly making "blorp" and "pling!" Sounds is genius

[@prietjepruck]

What a great explanation of the system behind soft body simulation I'm currently busy making my own project and this video helped a lot. I actually bought the game to compare your simulation with mine. Thanks a lot.

[@iamsushi1056]

What a blast from the past. Some of those levels were quite difficult.

[@littlegamerguy4803]

I can’t wait for this to release, this game was my childhood lol

[@giantisopod]

Ah yes, I remember playing this when it was still called JelloCar. Then a few years later everybody at my school started playing it on their iPods. I always wondered how it was implemented, so I was very excited to find this video on my KZbin front page today. Great explanation! I had always assumed it was more complex, but it seems like you can get away with a lot of approximations in game physics. That explains how it managed to run in real time on low powered hardware. Before this, I thought it might be some kind of FEM system, but that would probably be too slow...

[@amrosebirani]

This is amazing, loved the way you have described the entire physics setup. Thanks for inspiring !!

[@bixarrio5251]

Lovely. You make the complicated stuff sound so simple. Thank you, this was great!

[@Cameo221]

Beautiful video! This is awesome. Probably the best soft body explanation out there. ❤️

[@DrNo64]

KZbin is finally starting to reccomend me the type of content I actually want to watch!

[@Choolio94]

I played the original jelly car game so many years ago and loved it. I found you recently on TikTok. I was so excited for this game and I love these informational videos. I would honestly be even more interested in deep dives if you'd be willing to make them. I can't wait for the game to come out next month!

[@AlanZucconi]

This is such a good video! Thank you for taking the time making this! 🙏

[@EmilMacko]

For the point-in-shape collision detection, wouldn't it have been cheaper use the winding number method? That way you just calculate N angles for the N points in the shape, instead of calculating between 1 and some higher number of line intersections?

[@WalaberEntertainment]

Probably! It’s still N checks either way so it really depends on how you attempt to optimize the internals of the algorithm I think.

[@salmonsushi47]

You delivered every thing in a digestible way that anyone with a good knowledge of codding can recreate it THANKS!!! for the video you earned a sub.

[@678crazydave]

Incredible video. I used to play this game on the OG Ipod touch. You really explained everything clearly and concisely.

[@SeanStClair-cr9jl]

Awesome. Videos like these are so incredibly helpful, thank you!

[@juanma9868]

Well yeah this is it, this inspired me to try build this, it's so well explained, this is just a functional document, where now i can do a tech document of how to implement this and try to build this. Thanks man, i have a super hard time getting inspired to do things because i suck at creating ideas, im the kind of programmer that do stuff that others tells me instead of creating stuff, and this is the perfect content for me

[@namok-wx6xn]

jelly car and jelly train was my childhood man

[@lucbloom]

Greatest way to discover a fun game: a devlog.

[@TheGooEater]

This brings joy. Reminds me of Gish, i love that game.

[@johnsane2694]

Just a little fun fact: I am currently working on data augmentation for AI in cytology (cell images). I was looking for a way to simulate cell interactions and deformations and remembered the physics of JellyCar, which I played years earlier. Came here and found a really good working solution for my case! Thanks a lot! I'll mention you in the paper references :)

[@WalaberEntertainment]

Wow! Amazing, thanks for letting me know!

[@michaeljburt]

This video is incredible. It blew my mind quite a bit. Nice work!

[@sagrgywejhxcvx]

DEAR dude, I repeated everything you said, and it WORKS!!! thanks

[@warguy6474]

wow... I did not expect that collisison detection method

[@RoboMarchello]

Hello! Thank you so much! This video helped me a lot for my soft body simulation. soft body simulations are really fun topic. Gg on releasing jellycar worlds

[@TheChiptuner]

This video really makes me want to get more into game development. Fantastic vid, can’t wait for the full game’s release!

[@GuyThatCREATESRandomStuff]

12:01 looks like a 3D object

[@spaarm]

Jelly car was the first app I ever downloaded on my iPod touch years and years ago

[@cpt_nordbart]

Wow that takes me back a few years.

[@worthstream]

Your clever marketing plot has worked. I need to buy this! See you on Steam.

[@zehdread]

Super interesting! I'm curious, how did you do the conveyor belts? Do you actually move the point masses around or you hack the collision function and add a little tangent velocity to the final contact?

[@WalaberEntertainment]

the point masses on the conveyor belts are moving.

[@happyhorse7886]

Thank you so much for making this. Learned a lot!

[@judiethai9172]

Awesome video! I've been working on making a game where the character is a soft body, but only using Unity's 2D physics system and components. Glad that I ended up using a similar point-spring set up :D

[@barrettkepler7618]

Thank you for your video! I played your game on PSP when I was a kid and I had so much fun!

[@VyvyanTheGreat]

What a cool breakdown. Some of these implementations are super clever!

[@CreatorofSecks]

God, jelly car... how I miss this game

[@georginikoloff9280]

This video quality is god tier. Thanks for making this.

[@Notester82]

Wow, what an approachable look at what felt daunting to dive into at first! Also never would've thought about the technique you described for seeing if a point is inside of a shape or not, that feels clever. .u.

[@willd4686]

Thank you for making the Jelly Car games!

[@mylegispotato]

Whoa, you are the original creator of JellyCar 1 Originally played it on iPhone 3G, it was one of my favorite games. Games back then were so much cooler, no ads, well optimized and not overwhelming. Just what smartphones needed. Too bad it's probably just nostalgia. Loved it anyway!

[@WalaberEntertainment]

try out the new one and let me know if it's just nostalgia :P

[@john.dough.]

I haven't thought about this game in years! What a great video!

[@batner]

Thanks man! Very interesting. My hands are now itching to write something visual.

[@razi_man]

Wait... YOU'RE THE GAMEDEV OF JELLY CAR!?! I LOVE JELLY CAR! I still have the third Jelly Car game (Jelly Car 3) saved in my backup apps folder along with the save data backup!

[@WalaberEntertainment]

Amazing! You might want to join the discord, we are trying to archive all the classic levels and you might have some! There is a link on my website for the discord

[@rungeon83]

This was such a fantastic video, I'm very much a visual learner, but I'd have loved a long winded tutorial 😂. It gave me a lot to think about and I'm looking forward to trying a few techniques.

[@Heavenira]

This is SO digestible, i love it!!

[@guitarstuffig]

Omg I want to thank you for reminding me of this game from when I was a kid

[@jafsterlordbib]

Great stuff. Makes me wanna try some soft body physics

[@johnstevenson5084]

I loved jellycar on cool math games

[@ThylineTheGay]

Jelly car! Used to play it so much

[@AzureLow]

very good video and I learnt a lot! thanks, walaber! :)

[@DetectivePoofPoof]

Awesome video, great information and the game looks so fun I immediately bought it!

[@solcloud]

Really good examplanation and visuals. Thank you ❤

[@gammada1david57]

You can absolutely guarantee I’m telling as many people I know as I can about this game!!

[@whirlwind2831]

At 5:09 you mention how a certain point is moved more based on how close the colliding point is to one of the two edge points. What's the math behind it? And how much do we move them exactly so that the colliding point lands exactly on the newly formed edge is a little confusing. Can you please explain it?

[@WalaberEntertainment]

We know how far the point is from the edge. We calculate how much to move the edge and how much to move the point based on their relative masses. Then I just apply a “weight” to each point on the edge to move it between zero and the full amount, based on where the point is along the edge.

[@gmdrandom6287]

@@WalaberEntertainment I’m trying to implement weights but a problem is that sometimes a weighted line slant won’t align with the closest point causing the the point to still be in the line

[@fazbeark1ng]

this was my favorite cool math game :]

[@StefanHayden]

amazing video! Love long videos like these.