Hey everyone! I was inspired by 'BadAppleBot' (from the recent chess programming contest) to try and run Bad Apple inside of my fluid simulation project. To do this, I've taken the frames from the Bad Apple video and used the Jump-Flooding algorithm to calculate vectors for every frame that go from each pixel to the nearest pixel of the opposite colour. These vectors are then used to accelerate the particles (along with the pressure forces from the fluid sim of course). I recommend watching this in the highest quality you can, because compression will surely turn it to sludge. (You can also find a link to download the full-quality video in the description). If you'd like to play around with the project, it's currently in early access to Patreon supporters, but will be freely accessible in ~2 weeks.

if it can run code, it runs “Doom”. if it can play sounds, it plays “through the fire and flames”. if it can render, it renders “Bad Apple”. it’s the rule, no exceptions.

Engineers will spend countless hours making a particle based fluid simulation and then use it to make shitposts. Absolutely marvelous

I love the part at 1:41 there aren't enough particles for the character's body because of how the fluid got dispersed, but then when she reaches up, more particles flood in and make her outline clearer. Really neat interaction there

2:48 - The single most hydrophobic drop of liquid I have ever seen.

The man learned what Bad Apple is (from the chess tournament) and went straight for it lol

This unironically actually looks amazingly good

Sebastian has gone from not quite understanding the meme to making his own version. That's called growth.

I always laugh out loud whenever I see an insane bad apple video. A bad apple homage from Sebastian was the last thing that I had on my mind. God tier.

This will inevitably become the most viral video on this channel. Mark my words.

Man the "splash" when it goes from dark to fluid is so goddamn pretty, like 0:56 is so 🤩

I love how a bunch of the fluid flows directly into her shape at 1:43. Seeing the pressure constantly change and freak out was really fun.

This works really well because the bad apple animation is already really fluid

THIS LOOKS SO GOOD WHAT THE HELL ive seen countless iterations of this played over other "screens", but this is the first time ive gotten goosebumps for an entire bad apple video, specially the extra effects aaaaa i need the lossless videooo

Some of my favourite parts. 00:55 - The way Flandre* has the water settle within them, before violently EXPLODING into the background is a super cool visual. 01:38 - I just like how the water splashes around these two versions of Keine*, as they turn into that ball of light. The entirety of the section from 02:22 through 02:37... The splashes, yada-yada... The blue glow not quite keeping up with the visuals make it look even cooler. 03:00 through 03:11 starts out kinda incomprehensible, but the flower petals comprised of water look GORGEOUS. 03:20 - Funny how pretty much all the "water" in the music video is black, so there's no room for the water simulation to do anything funky. Still, that droplet turning into Reimu* looks great. I just love the transition of the colours, man, I'm no engineer, but this looks beautiful. * Corrections of character names provided by @HyperVanilo in the replies.

3:10 ngl when her hands appeared that was really cool

Jokes aside, this proves just how well-made the particle system is. It wasn't built to work for the video, but rather adapts to whatever is requested. Fantastic job making it render a full video!

Nice to see my favorite programming UKpostsr jump on the infectious trend of Bad Apple

The moment at 1:42 where the fluid from the ball flows into the outilne of the character is incredibly cool looking

1:24 looks SO GOOD! The sword swing is really extenuated by the particals moving

The best version of the video so far, the animation looks so fluid!

The sim adds so much fluidity (pun intended) to the original animation, it makes me think that it might be possible to have a fluid sim to assist in animating 3D characters by adding mesh deformation as a secondary animation.

The inevitability principle that anything will be turned to Bad Apple. This was a trippy experience, especially at 2:21

Wow this is amazing! The result is so smooth, I love it. Especially after seeing it too many times on an 8x8 grid. ;) As the author of BadAppleBot, I'm glad to have inspired you :)

This has to be one of the coolest renditions I've seen of Bad Apple

You're a genius. As someone who grew up with Touhou as his main game during childhood, and is now working around maths and simulations, I can safely say, what a time to be alive !

As someone who's had to deal with fluid simulations for the past 17 odd years, I fully appreciate every time the simulation looks like it's exploding from too fast of a state change

No wonder the channel name sounded so familiar!! You're the guy who made that globe-with-plane-game-thingy!! You're probably the last person I'd expect to make a Bad Apple cover

I've seen hundreds of these across all sorts of wild platforms, but this is one of the very few that I feel adds something new to the animation. The feeling of momentum, and the clever filling animation you did around 1:40, really elevate it. Really stand-out work.

welp let's see how popular this gets! nicely done. is this rendered in real time?

I've been following Sebastian Lague for years now and when I clicked on this video I was NOT expecting him LOL. Great work man

this is a completely different beast in 4k... watched it in 1080p and thought hmm... that's kinda neat. Watching it in 4k you can actually see most of the individual particles and flow of the fluid and it looks mindblowing. really cool 🙂

Ok, I did not expect this kind of video on this channel but I love it.

Unironically the best one. Those flashes when the contrast flips looks so dramatic when it's accompanied by the fluid simulation rapidly resettling.

0:56 I CANT STOP REWATCHING THAT PART

The amount of wallpaper potential is insane

2:05 *BRO, THIS LOOKS SOO COOL!!!*

1:30 using fluid simulation to simulate fire

0:54 Has to be the coolest part! I love the way the shockwave blasts out when the colors invert!

This is like a next level winamp visualizer! I love the contrast and colors, and interest the simulation adds without really detracting from the original

This is so unexpected and I love it, It's so smooth.

i can’t help but see the particles as bullets this has gotta be the mother of all spellcards

I'm amazed how 0:41 actually looks like dropping a cup into fluid

Clicked without even realizing it was a Sebastian Lague video! An interesting side effect of the simulation I noticed was that parts furthest/not connected to the fluid "blob" ended up not getting filled/rendered as quickly. Most noticeable at 3:29 when Reimu on the right is completely disconnected from the fluid and obscured, and also lead to a cool unintended effect at 1:43 where Eirin absorbs simulation particles from the moon. Unexpected but great video as always!

when i thought your channel couldn't get any better, you released this masterpiece, i always really appreciate your work

I've been watching a bunch of these over the last month, super cool to see you throw one up too. Good stuff.

"This is a bug. The simulation just did that when I ran it"

3:01: Recursive fluid similation

A real piece of art. Thanks Sebastian.

Woah, Mokou's flames turned out so cool!

This is one of the coolest BAs I've seen! Awesome

This is by far my favorite version of bad apple. Actually 2nd, because nothing will ever beat the crackheads that did it on r/place. But even considering that, it's still the coolest looking one.

The trend of Software Engineers putting Bad Apple into everything continues

I think it's funny that Bad Apple is like the perfect luma test 😂

The girl splashing the fluid as she dances across the screen at 2:13 is my favorite part

My boy Sebastian Lague making his own Bad Apple? That's a good start for the year.

3:19 Fluid-ception!

Amazing work

Oh my god. This actually gave me goosebumps, the visuals are so stunning.

Never expected something like this on your channel but it's great to see 😊 Probably my favorite Bad Apple edit too with the mesmerizing blue colors swirling around

This is one of the most seamless integrations of the video I've seen in any of these

0:21 this the most fucking magical bad apple witch anime women I've ever seen on youtube

incredible, thanks for this masterpiece sebastian

Half of my homepage consists of bad apple videos. This one is definitely one of my favourites, if not the best I’ve seen. Thank you a lot

looks absolutely insane

Looks like you’ve updated the sim code! That’s awesome. That pseudo surface tension around the border looks to be gone. Plus the overall movement looks to be more fluid. Looks awesome!

Ocean currents update lookin wild

this is so cool man great job!

This looks and feels like a screensaver from the early 2000s. Marvelous 💙

dang some of the moments in this are no joke some of the best most dynamic visuals I have ever seen wth

This is one of the most coolest stuff I have seen on youtube, specially involving programming. I watched the video on shitty youtube compression algo and I knew I had to watch the original one. Thanks for the link.

i don't know why, but the glowing kinda effect in the simulation brings me so much joy. it's just so mesmerizing to look at.

GOD DAMN THIS LOOKS SICK AS HELL! I like how the balls go out of bounds and then back in other shape.

Now this is what computer science was created for.

By far, one of the best Bad Apple entries I've seen so far! Well done!

This brings a smile to my face, thanks man!

The bit at 1:50 looks so cool

(Wild notification arrives) Yeah! New Sebastian Lague video!... ooh nooo

SO cool. Amazing work

This is incredible and makes an awesome video even more beautiful.

UKposts compression engine is working overtime

A piece of the image is missing here and there, most noticeable towards the end at 3:28, because so few of the particles made it to the other side.

This is one of the best Bad Apple remakes I've ever seen. The change of color the more dense the water is makes it look even nicer than just black-and-white.

This is really cool dude!!

0:11 it looks like she's blowing the particles away from her mouth

Not what I expected from you, but not complaining. Can't wait to see when this is the most popular video on your channel.

this is genuinely beautiful

This is the best version I have seen so far, it looks beautiful!

This may not be the most creative Way I've seen Bad Apple be played yet, but it's certainly a very cool-looking one! Usually I chuckle at whatever Tech was used for a Moment and then don't bother watching much longer. But this was actually really interesting to observe! Visually stunning!

Good day when Sebastian posts

I was not expecting this at all, and it was awesome!

OMG that's the coolest thing I'll be seeing this year. Well done Sebastian :)

It is a shame that the last scene is missing a character due to the fluid not going to them but this is otherwise fantastic!

He has actually lost the plot

a late christmas present I was not aware I needed. thank you sebastian :D

You nailed it bro!!

I don't know whether to be disappointed or impressed that Lague has implemented Bad Apple to add to the collection of remakes. Ah well. Edit: /j

3:16 Underrated moment, water flows down by the scythe, gets to the tip and then amass in the drop, really cool

This feels like a visual representation of my soul and I mean that in the best way possible

This is a video I never expected from Sebastian