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Cloth Simulation (oimo.io)
260 points by notmytempo on Aug 6, 2023 | hide | past | favorite | 43 comments



Fun Trivia: Feynman's son worked on cloth simulation for his MIT MSc Thesis back in '87!

https://dspace.mit.edu/handle/1721.1/14924


I believe Einstein's son worked on "Sediment Transport by Rivers". [0]

It must be hard for one to have a high-achieving--or worse, world famous--parent or sibling.

[0] https://en.wikipedia.org/wiki/Hans_Albert_Einstein


I don’t know, I think the cloth thesis looks like a good read, and Hans Einstein seemed to have had a very successful career.

I may be wrong, but I can’t imagine that any ridiculously gifted parent would care the slightest if their children fit the boots they leave behind. The hopes I have for my son is that he is happy, healthy, moral and enthusiastic. If he develops an interest in physics, electronics, programming, or any other thing we can nerd out together about, that’d be great - but if he develops a deep interest in whatever, that’s cool too. It would admittedly be very difficult for me to communicate with him if he doesn’t develop enthusiasm for anything.

At the moment he is leaning towards geology, but that’s because he’s 2 and likes collecting stones.


Imagine being in the Bach or Bernoulli where there was more than one…or being the third Manning brother (although he gets TV commercial time now)


Coded in lisp !


I did early work in mass-spring dynamics while at MIT (1985). My system was developed on a Symbolics Lisp Machine:

https://medium.com/@kaveh808/7-how-to-make-3d-jello-69350751...

I did simple fabric simulations, as well as 3d soft object dynamics.

Followup work in the early 90's on SGI workstations:

https://medium.com/@kaveh808/24-rubbery-cloth-and-numerical-...

All of this cloth and hair development culminated during my tenure as R&D lead on the feature film "Final Fantasy: The Spirits Within". The commercial Syflex system was an offshoot of that development.


TSW’s hair and cloth vfx crushed my brain in 2001, and those parts specifically still look pretty good to me today. Kudos!


Thanks. I wrote the hair generation software. It was a Maya plugin. For a very early (beta) version of Maya initially in 1997.


Playing with 3DS Max 5 in high school was such a “portal to the future” feeling. I loved the physics and cloth sims.

But come to think of it… has anyone ever seen a cloth simulation where the cloth can be more realistically rolled up or knotted, twisted, or otherwise doing things requiring a sense of volume and mass?


[SIGGRAPH 2017] Anisotropic Elastoplasticity for Cloth, Knit and Hair Frictional Contact: https://vimeo.com/219585631

If that doesn't do it for you, there's a lot more options in the SIGGRAPH paper list at https://kesen.realtimerendering.com/


For the Anisotropic Elastoplasticity for Cloth, Knit and Hair Frictional Contact - 2 minutes per frame. Hopefully we'll see things like this in realtime soon.


Absolutely unreal some of those demos.


Actually they're absolutely real looking ;p

But yeah, very mind blowing.


Exactly what I was seeking. Thank you. That shag carpet sim is incredible.


As an ex-3D developer, these videos are wild. Thank you.


Straight from the oven (paper from SIGGRAPH 2023): "Multi-Layer Thick Shells" (https://youtube.com/watch?v=z1Wc5DvC2Wk) Extends the FEM model to accommodate for thick shell-like structures, like yoga mats, leather, and wrinkles on matrices.

Also you might want to check out the IPC papers (particularily C-IPC, since you said you're interested in cloth: https://www.youtube.com/watch?v=jvBSDXxsgRA). A new class of simulation methods has arisen over the years which allow you to simulate detailed collisions in an incredibly robust way (though computation time is still an issue).


> though computation time is still an issue

This is what I got hung up on. I was doing some independent research on real-time cloth simulation for sailboats and I reached the conclusion that the physically accurate techniques are not real-time. I was looking at simulating tensions applied at specific vertices of the sail, the stiffness of the cloth, wind pressures, etc... and I gave up on finding anything that was doing it in real-time.

Am I wrong? Or is there a SIGGRAPH paper I haven't found yet :P


Have you looked into Small Step XPBD (introduced in the paper "Small Steps in Physics Simulation ")? It's the most efficient nonlinear dynamics integrator/solver I've come across, and luckily one of the simplest, too! (Keeping in mind that simplest nonlinear solver is a relative metric.) I've been able to simulate very stiff materials like bone by updating the sim at 6000 steps/second. The exact number of steps/second you'll need will depend on both the desired spatial resolution and physical accuracy of your sails, but I wouldn't be surprised if 6000 steps/second is more than sufficient. And computers are fast enough where you could simulate quite a few large, detailed sails at that rate in realtime.


Thanks for that link, I had not seen this paper before. I will add this to the backlog of things to try!


The channel @TwoMinutePapers on YouTube sometimes reports on progress in this area.

See this playlist: https://www.youtube.com/playlist?list=PLujxSBD-JXgnnd16wIjed...


Back when I was at Pixar, I remember hearing a lot about the cloth sims for Brave (2012). The clothing was heavily layered, with each layer adding volume. Here's one public article:

https://pixartimes.com/2012/04/09/close-up-the-amazing-desig...

"To achieve the mass of Fergus' kilt, the drape going across his chest has eight layers of cloth folded over and interacting with each other and other garments. The left, right and back sides of the drape have six layers each."

In motion:

https://www.youtube.com/watch?v=T1SBjAuMN6A

See also:

https://www.creativebloq.com/making-pixars-brave-8123080


There are a few amazing blendr plug-ins I've seen recently.

They have a workflow that is basically draw 2d patterns, stitch those together, then drape it over and let the simulation determine how it sits.

It seems like it's super powerful for clothing designers, and soft goods designers too.

YouTube has more info


How to use:

- Click on the sphere and drag towards the cloth.

- Click at any place and drag for wind.

Author's blog article (Japanese) https://blog.oimo.io/2021/06/17/spatial-hashing/

> Fast collision detection with Spatial Hashing

compressing the empty lattice it is an idea he came up with.


I remember when this was mind blowing, although not perfect, in Splinter Cell, on the Xbox, some 20 years ago. Now it’s almost flawless on my phone.



Nocturne (1999) was the first real use of cloth physics I saw in a game.


I remember Thief (1998) as having curtains that moved while hiding behind them.


Incredible that that was only 2 years after Quake, itself an astonishing advancement on the state of the art.


For a casino game studio, we needed an animation of a curtain dropping and waving in the wind. The artist render was crap. Bullet soft body cloth simulation did the trick. As a bonus, the curtain reacts to touch input. This was over 10 years ago.


I'm surprised how performant the home page is on my mediocre machine. Most dynamic pages perform much worse.


The same creator has some more really fun open source physics demos, click on the images: https://github.com/saharan/works In particular the clock and bubbles are nice and even run on iphone.


Very impressive. I use the cloth simulation in Daz Studio, and I wish it was as performant as this. It can take 20 mins only to have the cloth ‘explode’ when it intersects something unexpectedly. That said the obstacles are more complex than spheres


Seems like no collision is detected if you move the ball through the cloth fast enough.


Classic problem. Was/is also a problem with UK speed cameras IIRC. I think it was Top Gear that figured out if you drive something like 500 mph then it wouldn't register you speeding.


I also managed to twist the upper part in some kind of knot from which it's not recovering now.


Considering this works flawlessly on my iPhone X (due to be dropped with iOS 17), I have to say… really f*king impressive.


Nice. How long until I can scan my body with my iPhone and then try on virtual clothes so I can buy them if they fit me?


https://www.truetoform.fit/

https://www.beawear.ai/

The tech is mostly there, especially for the virtual fitting side; body scanning is the bigger problem afaik. There are people making dedicated body scanning stations which should be able to produce good quality avatar as one-time step.


There have been companies working on this for decades and I'm yet to see one that works well. Earlier versions used mechanically inflatable and modifiable mannequins to capture clothes on a variety of bodies, modern ones try and do the same with digital simulations, but they all fall flat compared to the real thing. In addition, if you think getting a sign up popup is annoying when you want to use a web page, imagine a page asking you to scan your body, never mind the privacy concerns.


My tailor did that the other day to make me a suit. He had a dark room with a scanner. It’s a different situation from what you want, but in principle I could use my 3D avatar as you say.


nice....

this looks to me a cotton "cloth"...

how about adding properties that it can act as a blanket or a silk cloth or a jute cloth or a tough starchy cloth or stuff like ironed shirt or unironed shirt?


Any way to have a second sphere?


and two more small ones...




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