A Repulsion Simulation! But Why? 🐰

[@Kram1032]

I love everything coming out of Keenan Crane's group and this was no exception

[@TwoMinutePapers]

Kram! One of our early Fellow Scholars - so happy to see you! I love their work too. So many amazing geometry papers are coming from there!

[@Kram1032]

​@@TwoMinutePapers watching every single one of your videos :)

[@TwoMinutePapers]

@@Kram1032 I was thinking about you the other day, wondering what you are up to. Such an honor, thank you! 🙏

[@Kram1032]

@@TwoMinutePapers The honor is all mine, thanks for introducing the world to so many phenomenal works

[@tariq3erwa]

For sure!

[@Solizeus]

This is simply amazing, specially if it doesn't break the bounds of the mesh, this could be the next cloths in games, forget about clipping through objects, this could save it by repulsing one of them or both, imagine this with grass and a foot messing around with it

[@richardduncan9740]

Finally the shrubs I wander though could deform properly instead of clipping! Outstanding!

[@coder0xff]

Check out this channels recent videos. There are some methods that are well suited to those kinds of problems.

[@111111222223]

My thoughts exactly. The navigation example also sound great for crowd avoidance. Only question I have, is it fast enough to be used in actual games or is only just fast enough for a showcase scene.

[@mercentperrault]

Days Gone has the most realistic facial animation I have ever seen in a video game

[@AmaroqStarwind]

Real-time 3D rendering with equally real-time anti-clipping?

[@djk1288]

I'm sure topologists will be going nuts over this stuff.

[@HerbaMachina]

Litterally what came to mind as soon as I saw it lol. This is a topologists wet dream.

[@pablojr4999]

I'm not a topologist, but I'm completely shocked by this. I mean, every mathematician must be.

[@CHOCOLATIONZ]

There would be a huge progress on the knot theory.

[@UNSCPILOT]

I'd love to see this as a tool in Blender in s few years, I could loose hours tinkering with this

[@NirvanaFan5000]

I'd love to see this applied to brain growth and wrinkles. Some people think brain wrinkles are adaptive, while others think that the typical brain folds and wrinkles are primarily due to the forces squishing the brain as it grows and the skull solidifies. Would be interesting to model brain growth in this and see if it produces characteristic physical human brain patterns.

[@toasteduranium]

+1

[@devilofether6185]

not a brain researcher or anything, but the presence of wrinkles suggests maximizing surface area, or conversely minimizing mass to volume. koalas are considered one of the least intelligent animals (compared to mass) on the planet, ant their brains have no wrinkles. there is a correlation, and I bet a causation between these factors.

[@NirvanaFan5000]

@@devilofether6185 : not disagreeing, but I've personally never read a good explanation as to why more surface area is helpful.

[@triangularlizard]

@@NirvanaFan5000 more surface area means you can cram more cells in less space think of it like shoving deflated balloons into a box, vs having to inflate the baloons. more surface fits in total due to the creases using space more effectively our lungs and intestines actually pull a similar trick! the lungs have alveolae that increase the surface area of the lung so we can absorb more oxygen the intestines have folds all along the inside of the tube for more cells that allow the absorption of nutrients and water along the surface area of the intestine itself well, for the brain it simply allows more individual braincells to be crammed in the limited space of the braincase, thus making us have more brainpower and a higher potential for intelligence than koalas and their smooth brains i hope this helped you understand why folds are useful!

[@NirvanaFan5000]

@@triangularlizard I don't understand why you think wrinkles would allow for more cells. if you can fit a 3lb dough into a bucket, you can't fit more dough in by giving it wrinkles.

[@gunsunnuva8346]

"And, if we feel like it, we can also start with a small piece of noodle inside a bunny and start growing it. ... over time it starts to look like intestines." Yep, that's a pretty repulsive paper after all, lol.

[@crnkmnky]

Bingo. 🙈

[@nyanSynxPHOENIX]

That's legitimately what I thought the video was about, but I was pleasantly surprised by math I guess.

[@ts4gv]

@@nyanSynxPHOENIX same here. An AI that had an understanding of what humans fond repulsive.

[@ellenino]

@@ts4gv same lol

[@GreasyBirb]

a couple uses off the top of my head based on my own experience. separating curves in a hair/fur groom for improved volume conservation. we can already do this at sim time, but that adds a lot of computational overhead. if this is cheaper it can simply apply the detangle/deintersect post-sim frame and keep things iterable. deintersecting non-trivial crowd agents (quadrupeds especially) as a sim postprocess would also be a benefit. again this usually has to be done at sim time and is incredibly prone to errors and rapidly inflating frame times.

[@HelixSnake]

These are two really practical applications of this tech which are easy to imagine being used frequently in a real world scenario. Thanks for this comment

[@pdjinne65]

Could be used, in general, for any dynamics sim as a startup state, yes

[@rogyx2289]

The most practical application I heard so far is for untangling tangled earbuds

[@stroopwafelfalafel]

I love that this insightful comment comes from someone with a he man profile picture

[@hesterclapp9717]

0:40 I find it fascinating it made a Hilbert curve without being programmed to

[@PIXXO3D]

Wow, this would certainly help with shrink-wrap applications, currently most shrink-wrap operations/modifiers produce lots of artifacts and overlapping faces. This is very exciting stuff 🙂

[@ffedor245]

I have not missed a video from you for a year now. Thank you for this thought-provoking and inspirational content. To the right person watching this, there are so many ideas you can derive from these papers. As an early career researcher in Molecular Biology, I hope in due time we will see content like this for every scientific field. Someone has to share those papers with a wider audience, not just hold on to them! Thank you for putting so much effort in that Károly!

[@indimediaworks]

Anton Petrov does this for science papers, mostly astrophysics on his channel kzbin.info/door/ciQ8wFcVoIIMi-lfu8-cjQ

[@ReynaSingh]

This has to be one of the best channels on this site. Keep it up

[@odesangel]

I totally agree. No other channel blows my mind with every new video the same way this one does. What a time to be alive!

[@zzzeval]

eggwuh

[@tanchienhao]

Applications in knot theory? Topology? What a time to be alive!

[@sigmata0]

If the path planning works well, could it be used to guide air traffic so as to both optimise and make safe the paths of aircraft in controlled airspaces?

[@davidmattes199]

Would this be a good paper to apply to protein folding? I'm no biochemist, but as I understand it all structures on the macro scale are defined by the atomic linking of matter and the shape it takes (folding). There is a whole decentralized process to compute folding experiments called Folding@Home that might benefit from this technique.

[@lava2istrue]

Well, I’m not a biochemist either, but I believe it would help. However, the nuances are numerous enough as to make it just that: help. protein folding is governed by more than just repulsive forces.

[@markarts404]

I can't say conclusively, but as a biochemist who is using AlphaFold2 in his current work and used Rosetta in a previous project, I'd say tentatively probably not... Rosetta is the closest piece of software to what you're suggesting; it applies individual forces to molecules (as opposed to AlphaFold2 which looks at all previously characterised proteins and uses deep learning to approximate what new sequences would look like). Rosetta is already reasonably intensive for large proteins and that's after already taking several shortcuts by subgrouping amino acids into trimers and heptamers and folding those first before having the subgroups interact with one another. If this method could be applied, I can only imagine it'd be more intense than Rosetta. And Rosetta is not always close to perfect (depends on the protein). But then again I'm not actually a bioengineer; I just use the software and don't actually do any coding. So I can't confirm for sure!

[@photelegy]

Exactly what I thought! That would be amazing!

[@davidmattes199]

@@markarts404 bioengineers use the software then?

[@markarts404]

@@davidmattes199 Bioengineers make the software, biochemists use it - imagine Photoshop vs Photoshop users (except with Rosetta it's best you at least have an understanding of the fundamental way the software works so you can interpret the results)

[@Ila_Aras]

Thank you for making these videos. Im always so excited for the next video!

[@TwoMinutePapers]

You are too kind, thank you so much! 🙏

[@Ila_Aras]

@@TwoMinutePapers no problem! I've been watching for at least a year now... It's so interesting seeing the progress!

[@epicthief]

This is oddly the most satisfying video to date, could watch these simulations all day

[@memeghost2425]

i love the little among us at 1:04

[@thedudeguy242]

Depending on how fast it is, it'd be very nice for crowd simulations. I'm also curious if there's a trivial way to constrain the points/curves to a mesh

[@Kram1032]

that it is quite fast is a big point of the paper

[@dan339dan]

0:50 I immediately recall the "How to turn a sphere inside out" video. "Remember, you mustn't tear or crease it" 😂

[@cenigma]

Thank you for your service :)

[@TwoMinutePapers]

Thank you so much for your generous support Danny! 🙏

[@PatchCornAdams723]

This is your best video to date. I was NOT able to hold onto my papers for this one.

[@jupitersky]

When I saw the hilbert curve happen in the intro I literally jumped out of my seat with excitement.

[@BJCaasenbrood]

For those interested in this work, I can highly recommend the online youtube courses from Keenan Crane on discrete differential geometry (he is a co-author of this work). They are one of the best lectures I've seen thus far.

[@HilbertXVI]

I knew his name was familiar!

[@Alorand]

6:13 I finally pull the trigger on buying wireless earbuds, and then they invent a way to keep the wires untangled...

[@tiusic]

I'd use it to upgrade graphviz. It's a tool that's used to visualise graphs, like that social media graph example. This paper would produce much more readable graphs. So many things in computing can be represented as graphs, so being able to visualise them in a readable way is really useful for debugging.

[@martiddy]

I was expecting an animation of how to turn a sphere inside out with this technique.

[@revengefrommars]

Applying this to protein folding could be interesting.

[@getsideways7257]

I believe that could revolutionize the field, actually.

[@btat16]

I remember the game Foldit that came out a while ago that attempted to crowdsource certain folding problems

[@getsideways7257]

@@btat16 Indeed. Although it was hard to qualify it as "a game', but it was a rather curious piece of code in its own right.

[@maracachucho8701]

It would need heavy tweaking to account for all the molecular forces involved but yeah, it would be interesting indeed.

[@nbrayn]

Bingo!

[@MCGeorgeMallory]

In pretty much every video on this channel, you always seem to find the paper way more excited than I am, even with exciting videos, but in this case, I spent the entire video wondering why you weren't reacting to just how truly amazing and useful this one is! My mind is now buzzing with all sorts of interesting applications for this! I finally understand why you're so excited in every video: it's to strike a happy medium between the attitudes of your viewers. Thanks for the amazing content!

[@dsp4392]

This could definitely be used to improve clothing in games with character editors allowing diverse body types.

[@DevashishGuptaOfficial]

Love Keenan Crane's entire body of work so much!

[@trevorhook5677]

It would be cool to see npcs walking through a town/village and using repulsion as both a deterrent for intersection as well as a measurement of distance before an npc needs to stagger or come to a complete stop before running into another npc, or even use repulsion to define a distance between npcs and players where npcs will path around or nod at/greet characters to create a realistic and immersive environment. Really cool stuff!

[@Invalid571]

This tool seems like a topologist's best friend.

[@ChunkyChest]

I wonder if this can be applied in knot theory topology 🤔

[@michaelleue7594]

I usually have a sense of how the implementation of ideas would actually work, at least in general. But this, I don't understand how this can be done. This is exactly the thing graphics designers have needed since literally the beginning of computer graphics being a thing, and the applications are unending, but just...how?!

[@diablo.the.cheater]

They summoned the computer spirits and learned their black sorcery?

[@ethanblanke6873]

Assuming this technique can be refined to the point where it can work in real time, the non-intersecting curved paths part mentioned at 3:57 suggests an application in a self-driving cars network. It could almost eliminate the need for stopping and waiting at intersections, as speeds and trajectories would be pre-calculated not to collide. Entire traffic light systems could be replaced with an intersection computer that communicates with and directs autonomous vehicles in and around the intersection. Idk that’s just what stood out to me

[@MrRastique]

This one folks-this channell is top of the notch. Thank you for yor videos. At least we know what are the possibilities for future. WHAT A TIME TO BE ALIVE👍👍👍

[@thesuccessfulone]

I love this paper. It really shows how repulsive curves can effectively fill a space with no intersections, like in our brain or digestive tract.

[@sonman3694]

You should show more of the path finding using this technique, very interesting!

[@devilofether6185]

This would also be perfect for plant growth simulations, since plants adapt to their surroundings. an example of this is crown shyness, where trees will avoid stealing light from other similar trees.

[@rogyx2289]

That moment when you're to lazy to untangle your headphones so you build a whole Repulsion Simulation to untangle them for you

[@kylebowles9820]

Wow that manifold optimization was really good, computational techniques are getting really good

[@markbee790]

this is an important piece, a discreet but fundamental advance in physical modelling, the question is what wouldn't i use it for, so glad to see many commenters see the potential also

[@andrut]

Károly, what are you doing to me?! I should be working and now I will be reading this paper on fascinating stuff I didn't know I needed in my life just 10minutes ago. And that's not the first incident of this sort. No, really thanks for your channel and work you're doing.

[@apolloandwarrior_3229]

I don't know what any of this is but your commentary and explanations are just so interesting to listen to

[@collin4555]

Movement path planning is a neat application for it, but how quickly does it compute those paths?

[@shadamethyst1258]

How does it fare in protein folding simulations?

[@Roxor128]

This could be useful for designing printed circuit boards. Take your electrical schematic and component dimensions. Confine the movement of the components to a plane and use the repulsion simulation to figure out where to have the connections go, maybe adding constraints, such as minimising the size or fixing the locations of certain parts. As an example, if you're a retrocomputing enthusiast and you're designing a new ISA card, you'd fix the location of the pads for the ISA connector, limit the external connectors to the right edge of the board (but allow them to be anywhere along it), impose a maximum length and height and ask the program to try and minimise the board size.

[@KuraSourTakanHour]

I'm not a scholar computer science, simulations etc but I just find it fascinating to watch and learn how ingenious AI and algorithms are solving problems and also the potential creative uses that emerge

[@shruikan1962]

Wow! That part where the video described pathfinding makes me think it can be combined with smart-car driving AI and logistics. Most people think about having cars communicate with each other but this makes me think about a server with this repulsion tool to map out the routes of thousands of cars at a time, using repulsion to stop any collisions. If you can add obstacles while it's mapping then you can also use it for cargo ships too so they can go around accidents

[@bloomp7999]

exactly what i needed, i was thinking of nodes in editor softwares that can get very messy, with this you're good

[@MuhammadHanif-bx4pb]

now if we reverse this repulsive force with attractive force without overlapping, we can simulate protein folding. also by adding a goal shape and train a neural network to achieve certain shape for the active region of the protein we have general protein solving model.

[@ProjectPhysX]

Finally I am educated on the anatomy of Stanford Bunny!!

[@Nekuzir]

Oo, I was planning on building a new tower defense game that brings back the old td strategy of mazing. I'd love to be able to use this to help build the paths a.i. use to travel along your maze, but also maybe use it to build a.i. that can plan out mazes too

[@mortyforty8404]

A video game based on this tech would be amazing. I have no idea how it would work!

[@Yezpahr]

6:06 I would try to turn hypercubes into single cubes to extrapolate how the time dimension forms our world. I have a feeling it's just swirling around until it looks like 1 cube. It might even manage to visualize 7 cubes next to each other from 1 hypercube.

[@tealquoise1437]

I wonder if the shrinking method could be used to create more efficient Bounding Volume Hierarchies. There's a cost to compute the shrunken shape up front, but for complicated geometries - where the approximation of a bounding box or sphere doesn't give a good fit - this would probably be worth it. It could maybe even be used to help with collision detection of deformable objects. Or maybe it could help with raytracing by minimizing the surface area of bounding volumes: start with your AABB, then run the shrink algorithm to give a better fit around your shapes, and do that for each node in the tree.

[@PaigeWylderOwO]

This video reminds me of a video essay about the mathematics of turning a sphere inside out (source here: kzbin.info/www/bejne/rYCZYndvrZufhLs&ab_channel=ssgelm), but this one concisely demonstrates practical applications in the real world including: -Untangling bound objects in the real world -Designing graphical or physical objects that maximize for the highest/lowest volume to surface area ratios for applications like packaging, visual aids, or object physics in games and -And avoiding collisions, which will be useful for autonomous vehicle traffic

[@piovertwoo]

Keenan crane is one of the best we have, highly recommend checking out anything he’s done…and for sure one of the most beautiful thesis papers I’ve come across!

[@Pheonix1328]

I really liked how the second "trivial implementation" (@ 5:30) looked like some kind of alien being growing or something.

[@Mayyde]

"Is this it? Is this turning a sphere inside out?"

[@npeters97]

With a background in psychology and neuroscience, of course my first thought is cortical sulci and gyri. I imagine other structures of the nervous system would be well modeled this way, as well. Very interesting, thanks.

[@official-obama]

I once saw a knot theory explanation and they said it was incomplete because once you generate a knot you can’t untangle it and find what knot it is, or if it’s a new one

[@VictorCampos87]

Can this be used to perform faster (or better) protein folding simulations?

[@johnpekkala6941]

Very Interesting concept I have not thougt of before! Also im gonna try to model and 3D print those last shapes at the end. They looked cool! :)

[@AaronMorrisTheSteamFox]

Excellent presentation as always! Would love to see this and fluid simulations used to simulate the physical properties of such things as soup with noodles and other stringy or flexible foods in full-immersion VR! I know it's still a ways off, but your videos make me excited for the day we no longer need traditional rasterized graphics and clunky headsets in order to enjoy virtual worlds!

[@roryrose8445]

1:22 make me remember about video titled "outside in" video describing about how a sphere turning inside out, very funny and fascinating educational video xD

[@besknighter]

Path planning for vehicles? If it's possible to implement this algorithm in a way that each entity can calculate their own path based on a section of other nearby entities paths in such a way that it's locally (both distance and time) coherent, maybe there won't be any need for traffic control. Maybe. 😅

[@Rurattee]

I'm extremely grateful to have taken a class with Keenan last semester He's a great teacher and a great researcher

[@blockflight]

great video. i always fascinates me when a global problem can be solved locally. it reminds me of some research one of mine professeurs did, where instead of air traffic controllers the only rule basically was that any manoeuvres had to be away from the closest encounter. it was crazy effective, they could get multiple times the aircraft density of the busiest european airspaces, and pilots still complaining that there weren't enough aircraft and it wouldn't work if it's was busy (while being 2-3 busier than that).

[@sitkinator]

4:01 this one interests me cause it could be used for making videogames more immersive imo.

[@sjzara]

Shrink wrapping of point clouds could be amazingly useful for land surveying - volume calculations and contouring.

[@musikdoktor]

Excellent Paper!! I loving it!

[@neckkeys5251]

When seeing this idea I thought about Lagrangian liquid simulations (SPH for example). This kind of simulation can suffer from particle collapses or volume inconsistency which is sometimes fixed by the expensive computing of solving of the Poisson equation. Maybe the idea of this article can find applications in Lagrangian liquid simulations to conserve volume.

[@AM-zc9mq]

To ascertain the proximity or the object in the scene one has to do some form of proximity test and the in itself will be somewhat of an intersection test with a an object of larger dimension that is just not visualized. I just don't get how one can affirm proximity programmatically without checking for intersections.

[@General12th]

I just realized a potential utility for this algorithm being able to work on incomplete point clouds: sensory data! If we have cameras, rangefinders, sonar, etc. that are analyzing the obstacles around an object, this algorithm might provide an accurate and efficient way of creating a smooth mesh between all those points. What a time to be alive!

[@mar_sze]

The ideas that are simple and have many applications are always the biggest breakthroughs.

[@ThomasConover]

Two minute papers, your skills in discovering and publishing entertaining and highly educational videos about advanced algorithms is nothing less than amazing. 😎😎😎👍

[@serta5727]

A very neat little technique with many useful applications Awesome 😎

[@jimmyjoe1488]

This could be used to procedurally generate unique, and pleasing-looking, towns and cities whose arrangement make sense. It could mold the cities to a landscape such as a cliff, without roads and buildings being generated on the sides, or bottom of the cliff. Fantastic applications for procedural generation.

[@100thfail]

I stumbled upon this knowing nothing about neural networks or digital design, but this was neat to watch

[@bryanharrison3889]

I've been watching these videos for so long that I started making sure I have a paper handy so that I can hold on to it ans squeeze it as needed.

[@alessi4249]

I wonder the applications in PCB autorouting

[@getsideways7257]

That's another good idea

[@Roxor128]

This was my thought, too.

[@badradish2116]

STOP MELTING MY BREAIN I NEED IT

[@royalty-freevideos1780]

Can this be used in traffic for self-driving cars to eliminate traffic signals?

[@0MVR_0]

The 'shrink wrap' process could be used for distance-based downscaling, aliasing, load-on-distance, or procedural clothing.

[@Roxor128]

The clothing one has a lot of room for making life easier for artists working on sci-fi games. Use the shrink-wrap process to fit a surface a small distance out from an alien's body, then cut off the parts you don't want covered by that outfit, then refine the rest into a suitable style.

[@Nonkel_Jef]

Could this be used to simulate protein folding?

[@erikprallon2813]

Could it be used in a network of self driving cars to promote perfect coordination and replace traffic lights?

[@HerbaMachina]

No. This is way to simple an algorithm for that use case.

i'd use this for generative art, it looks similar to differential line growth

[@favesongslist]

I was interested in the collision avoidance application, surely this has great value.

[@jocrane01]

protein folding would be a cool application

[@dogindagrass]

woah, topology is a weird field! Amazing they're working out all this stuff!

[@NutScrewGamer]

Finally. We will have a robot untangling cables for us

[@Sarimae23]

the blood-system fe ^^ if you specify perimeters, you can extreeemely well make blood systems in artificial bodys for research Also, other ventricular systems, of course..Trees...funghi... everywhere, where you need the "inner systems "to be precise for simulations.

[@sampark3502]

thanks again for showing another great paper! my immediate thought is that it can put to good use for FAA flight (drone or airplane) path planning simulation or self driving car!

[@aaronwhite5803]

This feels like it might have some use for simulating protein folding, but I don't know enough about that to be sure about it. Still cool as hell though.

[@josephlondon8188]

This made me think of turning a sphere inside out without any intersections, what a classic of the internet

[@madscribbles]

I've always wanted to be able to build a chart with large number of items thay have an arbitrary number of connecting lines between them and then have some kind of algorithm find the best arrangement for the items to minimize the amount of stretching and crossing of connections.

[@nikytamayo]

This would be great for optimizing wiring channeling for automotive or aerospace components.

[@cbuchner1]

I‘d probably use it to design rabbit shaped sex toys.

[@geneticallygamer]

im really excited for the future of shrinkwrap just one click sw would be so satisfying and time saving

[@gabrielxavier2676]

I think the low hanging application seems to be logistics and automatic traffic control for autonomous vehicles Some of the most novels could be Proteins folding/unfolding, dark matter studies or 3D printing infill techniques. Not that it would be necessarily revolutionary in any of them, but it could be used in models.