# Stanford Invented The Ultimate Bouncy Simulator! 🏀 ## Метаданные - **Канал:** Two Minute Papers - **YouTube:** https://www.youtube.com/watch?v=55PJtqpXAm4 - **Дата:** 08.01.2022 - **Длительность:** 5:55 - **Просмотры:** 112,603 ## Описание ❤️ Check out Lambda here and sign up for their GPU Cloud: https://lambdalabs.com/papers 📝 The paper "Bounce Maps: An Improved Restitution Model for Real-Time Rigid-Body Impact" is available here: https://graphics.stanford.edu/projects/bouncemap/ 📝 The amazing previous works: - Input video, output sound - https://www.youtube.com/watch?v=kwqme8mEgz4 - Input sound, output video - https://www.youtube.com/watch?v=aMo7pkkaZ9o ❤️ Watch these videos in early access on our Patreon page or join us here on YouTube: - https://www.patreon.com/TwoMinutePapers - https://www.youtube.com/channel/UCbfYPyITQ-7l4upoX8nvctg/join 🙏 We would like to thank our generous Patreon supporters who make Two Minute Papers possible: Aleksandr Mashrabov, Alex Balfanz, Alex Haro, Andrew Melnychuk, Angelos Evripiotis, Benji Rabhan, Bryan Learn, Christian Ahlin, Eric Martel, Gordon Child, Ivo Galic, Jace O'Brien, Javier Bustamante, John Le, Jonas, Kenneth Davis, Klaus Busse, Lorin Atzberger, Lukas Biewald, Matthew Allen Fisher, Mark Oates, Michael Albrecht, Michael Tedder, Nikhil Velpanur, Owen Campbell-Moore, Owen Skarpness, Peter Edwards, Rajarshi Nigam, Ramsey Elbasheer, Steef, Taras Bobrovytsky, Thomas Krcmar, Timothy Sum Hon Mun, Torsten Reil, Tybie Fitzhugh, Ueli Gallizzi. If you wish to appear here or pick up other perks, click here: https://www.patreon.com/TwoMinutePapers Thumbnail background design: Felícia Zsolnai-Fehér - http://felicia.hu Wish to watch these videos in early access? Join us here: https://www.youtube.com/channel/UCbfYPyITQ-7l4upoX8nvctg/join Meet and discuss your ideas with other Fellow Scholars on the Two Minute Papers Discord: https://discordapp.com/invite/hbcTJu2 Károly Zsolnai-Fehér's links: Instagram: https://www.instagram.com/twominutepapers/ Twitter: https://twitter.com/twominutepapers Web: https://cg.tuwien.ac.at/~zsolnai/ ## Содержание ### [0:00](https://www.youtube.com/watch?v=55PJtqpXAm4) Dear Fellow Scholars, this is Two Minute  Papers with Dr. Károly Zsolnai-Fehér. Today we are going to design a crazy baseball  bat, a hockey stick that’s not working well,   springs that won’t stop bouncing, and  letters that can kind of stop bouncing. And, yes, you see it correctly, this  is a paper from 2017. Why? Well,   there are some good works that are timeless.   This is one of them. You’ll see why in a moment. When I read this paper, I saw that it is  from professor Doug James’s group at Stanford   University, and at this point, I knew that crazy  things are to be expected. Our seasoned Fellow ### [0:45](https://www.youtube.com/watch?v=55PJtqpXAm4&t=45s) Water Step Scholars know that these folks do some absolutely  amazing things that shouldn’t even be possible. ### [0:50](https://www.youtube.com/watch?v=55PJtqpXAm4&t=50s) Pouring Faucet For instance, one of their earlier papers takes an  animation and the physics data for these bubbles,   and, impossible as it might appear,  synthesizes the sound of these bubbles. So,   video goes in, sound comes out.   And hold on to your papers because that’s  nothing compared to their other work,   which takes not the video, but the sound  that we recorded. So, the sound goes in,   that’s easy enough, and what does it do? Creates  a video animation that matches these sounds.    That’s a crazy paper that works exceptionally  well. We love those around here. And, to top it off, both of these were handcrafted  techniques, no machine learning is applied.    So, what about today’s paper? Today’s paper  is about designing things that don’t work,   or things that work too well. What  does that mean? Well, let me explain. Here is a map that shows the physical  bounciness parameter for a not too exciting   old simulation. Everything, and every part  does the same. And here is the new method.    Red means bouncy, blue means stiff. And now, on to the simulation. The old one  with the fixed parameters. Not bad, but it not   too exciting either. And, here is the new one.   Now that is a simulation has some personality. So, with this, we can reimagine as if parts  of things were made of rubber, and other parts   of wood or steel. Look. Here, the red color on the  knob of the baseball bat means that this will be ### [2:52](https://www.youtube.com/watch?v=55PJtqpXAm4&t=172s) Example: Baseball Bat made bouncy, while the end will be made stiff. What does this do? Well, let’s see together.    This is the reference simulation where  every part has the same bounciness. And now,   let’s see that bouncy knob. There we go!   With this, we can unleash our artistic vision   and get a simulation that works properly,  given these crazy material parameters. Now, let’s design a crazy hockey stick. This  part of the hockey stick is very bouncy, ### [3:22](https://www.youtube.com/watch?v=55PJtqpXAm4&t=202s) Example: Hockey Stick & Puck this part too, however, this part will be  the sweet spot, at least for this experiment.    Let’s hit that puck and see how they behave.    Yes, from the red, bouncy regions, indeed,  the puck rebounds a great deal. And now,   let’s see the sweet spot. Yes, it rebounds  much less. Let’s see all of them side by side. Now, creating such an algorithm  is quite a challenge. Look,   it has to work on smooth geometry, built  from hundreds of thousands of triangles.    And one of the key challenges is that the  duration of the contacts can be… what?! Are   you seeing what I am seeing? The duration of some  of these contacts is measured in the order of tens   of microseconds. And, it still works well, and  it’s still accurate. That is absolutely amazing. Now, of course, even though we can have  detailed geometry made of crazy new materials,   this is not only a great tool for artists.   This could also help with contact analysis,   and other cool engineering applications where we  manufacture things that hit each other. Glorious. So this is an amazing, timeless work from 2017,  and I am worried that if we don’t talk about it   here on Two Minute Papers, almost no one will  talk about it. And these works are so good,   people have to know! Thank you very much for  watching this, and let’s spread the word together! Thanks for watching and for your generous  support, and I'll see you next time! --- *Источник: https://ekstraktznaniy.ru/video/13707*