[HN Gopher] Cloth Simulation
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       Cloth Simulation
        
       Author : adamch
       Score  : 183 points
       Date   : 2025-12-02 22:44 UTC (8 days ago)
        
 (HTM) web link (cloth.mikail-khan.com)
 (TXT) w3m dump (cloth.mikail-khan.com)
        
       | iberator wrote:
       | Maya and Cloe 3D and almost all fashion design software have it
       | for decades already. Niche and fascinating software. Check out
       | some demos.
       | 
       | Cool stuff in software you don't even know exists:)
        
         | zokier wrote:
         | Of course cloth sims of varying fidelity are everywhere. Even
         | games have had cloth sims for decades at this point.
         | 
         | But it is also something that remains a research problem how to
         | do efficiently and with good results; pretty much every year in
         | siggraph you see couple of new papers around cloth sims. For
         | example this year we got this https://youtu.be/d9TZhtXeMio
        
           | ChrisMarshallNY wrote:
           | As an artist, I needed to get it right. Wasn't as easy as I
           | thought it would be. I had to think in 3D, to make 2D.
           | 
           | https://littlegreenviper.com/art/Tarsus.png
           | 
           | https://littlegreenviper.com/art/Gym.png
        
             | fao_ wrote:
             | One of the best ways to practice this is just throwing a
             | towel on a chair, sitting down opposite it, and sketching
             | it
        
           | regularfry wrote:
           | The cloth sim in Blender remains one of the most
           | frustratingly un-updated features. I would dearly love to see
           | it get an algorithmic refresh.
        
             | brontosaurusrex wrote:
             | At least solver seems faster (if not better) in later
             | versions? p.s. My try at 'flag in the wind' in Blender from
             | around 2022:
             | https://0x0.st/s/aJ6DNj2pEHzRdBiscEIsbQ/KCsK.mp4 I do
             | remember it took me all day to get somehow realistic
             | motion.
        
       | Miraltar wrote:
       | Exactly as discussed in Sebastian Lague's video
       | https://www.youtube.com/watch?v=PGk0rnyTa1U
        
         | TwoFx wrote:
         | I highly recommend watching the relevant section of that video
         | (4:38 to 8:59) and then implementing it yourself in whatever
         | system you know that can draw lines and circles (I did it in
         | Godot; it took only a few minutes to learn enough Godot to
         | start on the algorithm).
         | 
         | It's absolutely mind-blowing that so little code can produce
         | such a beautiful result. It's also fun to play with the
         | parameters and see how they affect how the cloth feels.
        
           | mclau153 wrote:
           | would you share your godot code to github?
        
       | atan2 wrote:
       | A very nice article by Marian Pekar on Verlet integration and
       | cloth simulation:
       | 
       | https://pikuma.com/blog/verlet-integration-2d-cloth-physics-...
        
       | jeffreygoesto wrote:
       | For me, "Large Steps in Cloth Simulation" [0] made implicit
       | methods accessible... Seminal paper.
       | 
       | [0] https://dl.acm.org/doi/10.1145/280814.280821
        
         | chombier wrote:
         | For inextensible cloth there's also "Efficient simulation of
         | inextensible cloth" [0] that is particularly clever and
         | efficient
         | 
         | [0] https://dl.acm.org/doi/10.1145/1276377.1276438
        
       | bogtog wrote:
       | It tearing when I waved my mouse around was a nice surprise
        
       | clbrmbr wrote:
       | The tearing was unexpectedly disturbing!
       | 
       | Suggestion: use an accelerometer data on mobile and use that to
       | directly replace gravity. I expect to be able to tip the phone to
       | drape the cloth, and shake the phone to get waves of motion.
        
         | Hobadee wrote:
         | This.
         | 
         | I can tear real cloth if I try, but I need to try. A flick of
         | the finger has never once in my life torn cloth.
        
           | afandian wrote:
           | Clear you must bite your nails!
        
           | fainpul wrote:
           | Literally unplayable
        
           | brookst wrote:
           | It feels a bit like shooting at cloth.
        
         | eddieroger wrote:
         | I think the little tears were fine, but my expectation of the
         | weight of the cloth wasn't so much that it would start to rip
         | on its own after a certain point. It felt more like a wet dough
         | at a certain point than cloth.
        
       | jan_Sate wrote:
       | Looks like that I can cut it without right click by swiping fast
       | enough.
        
       | taeric wrote:
       | First, kudos on this. Really cool to play with.
       | 
       | Reminds me of a great video not long ago that went over the main
       | ideas behind weaving and knitting. Feels like you almost
       | certainly have to take some of those ideas in mind when doing a
       | simulation like this. Would be curious to read a breakdown of how
       | this was made and how it incorporates the concepts that go into
       | different fabric.
        
       | OptionOfT wrote:
       | I remember the first time playing Splinter Cell.
       | 
       | Walking back and forth through a curtain to see how it wraps
       | around the body. So cool.
        
       | RankingMember wrote:
       | Pretty cool! I kept trying to cut the piece I had just cut again
       | by doing a "Zorro"-style motion, but no such luck.
        
       | samcheng wrote:
       | This is great! The only part that broke the immersion (for me)
       | was that the cloth bits fell at a constant rate - I'd expect them
       | to accelerate due to gravity, and maybe flutter as they fell.
       | 
       | Nice art!
        
       | robertheadley wrote:
       | I wonder how far away we are from realtime Marvelous designer in
       | games.
        
       | mrkramer wrote:
       | Reminds me of Fruit Ninja but this one is Cloth Ninja.
        
       | LyalinDotCom wrote:
       | I was curious and was able to build something very similar
       | quickly using Gemini 3 via Google AI Studio. Never would have
       | imagined a few years ago how easy some of this has become to
       | prototype.
        
         | cyber_kinetist wrote:
         | There's a lot of simple cloth sim examples on the internet, so
         | I see why LLMs can code these kinds of demos easily.
        
           | LyalinDotCom wrote:
           | yeah makes sense. Im sitting here evolving my little
           | prototype its too much fun.
        
         | jcims wrote:
         | The 'Build' feature in AI studio has been pretty incredible for
         | a few use cases I've thrown at it.
        
       | hoppersoft wrote:
       | I spent entirely too much time finding out exactly how much
       | "cloth" could be supported by two "strings."
        
         | zenoprax wrote:
         | I'm going to assume it is "more than you think; not as much as
         | you'd like" because I don't have the time to burn this morning
         | to replicate your research.
        
       | cloudfudge wrote:
       | It's rust compiled to wasm. Dude's got a lot of interesting stuff
       | on his projects page: https://mikail-khan.com/portfolio
        
       | jakemanger wrote:
       | That's super cool (and FAST -> hard to do from my personal
       | attempts).
       | 
       | But, please, give us some nitty gritty of how you made it
        
       | raylad wrote:
       | Feels more like a spiderweb simulation. The fibers are sticky and
       | stretchy.
        
       | flet wrote:
       | I like it!
       | 
       | I made this a bit ago for fun and funnies to test the idea of
       | tearaway ads. It's very prototype but still pretty satisfying
       | (desktop only but there's a gif on the repo)
       | 
       | https://github.com/Flet/tearaway
        
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       (page generated 2025-12-10 23:01 UTC)