# Interactive Hair-Solid Simulations | Two Minute Papers #90 ## Метаданные - **Канал:** Two Minute Papers - **YouTube:** https://www.youtube.com/watch?v=HvHZXPd0Bjs - **Дата:** 29.08.2016 - **Длительность:** 3:22 - **Просмотры:** 15,322 - **Источник:** https://ekstraktznaniy.ru/video/14782 ## Описание We have talked about fluid and cloth simulations earlier, but we never really set foot in the domain of hair simulations in the series. To obtain some footage of virtual hair movement, simulating the dynamics of hundreds of thousands of hair strands is clearly too time consuming and would be a flippant attempt to do so. In this episode, we discuss a technique to faithfully simulate 150 thousand hair strands by using only 400 guide hairs. ____________________________ The paper "Adaptive Skinning for Interactive Hair-Solid Simulation" is available here: http://gaps-zju.org/mlchai/resources/chai2016adaptive.pdf http://gaps-zju.org/mlchai/ Two Minute Papers offers great perks to supporters on Patreon: https://www.patreon.com/TwoMinutePapers WE WOULD LIKE TO THANK OUR GENEROUS PATREON SUPPORTERS WHO MAKE TWO MINUTE PAPERS POSSIBLE: David Jaenisch, Sunil Kim, Julian Josephs, Daniel John Benton, Dave Rushton-Smith, Benjamin Kang. https://www.patreon.com/TwoMinutePapers We also thank Ex ## Транскрипт ### [] Dear Fellow Scholars, this is Two Minute Papers with Károly Zsolnai-Fehér. We have talked about fluid and cloth simulations earlier, but we never really set foot in the domain of hair simulations in the series. To obtain some footage of virtual hair movement, simulating the dynamics of hundreds of thousands of hair strands is clearly too time consuming and would be a flippant attempt to do so. If we do not wish to watch a simulation unfold with increasing dismay as it would take hours ### Gears [0:29] of computation time to obtain just one second of footage, we have to come up with a cunning plan. A popular method to obtain detailed real-time hair simulations is not to compute the trajectory of every single hair strand, but to have a small set of strands that we call guide hairs. For these guide hairs, we compute everything. However, since this is a sparse set of elements, we have to fill the gaps with a large number of hair strands, and we essentially try to guess how these should move based on the behavior of guide hairs near them. Essentially, one guide hair is responsible in guiding an entire batch, or an entire braid of hair, if you will. ### Combing [1:12] This technique we like to call a reduced hair simulation, and the guessing part is often referred to as interpolation. And the question immediately arises: how many guide hairs do we use and how many total hair strands can we simulate with them without our customers finding out that we're essentially cheating? The selling point of this piece of work, is that it uses only 400 guide hairs, and leaning on them, and it can simulate up to a total number of 150 thousand strands in real time. This leads to amazingly detailed hair simulations. My goodness, look at how beautiful these results are! Not only that, but as it is demonstrated quite aptly here, it can also faithfully handle rich interactions and collisions with other solid objects. For instance, we can simulate all kinds of combing, or pulling our hair out, which is ### Hand Grabing [2:07] what most researchers do in their moments of great peril just before finding the solution to a difficult problem. Not only hair, but a researcher simulator, if you will. The results are compared to a full space simulation, which means simulating every single hair strand, and that is exactly as time consuming as it sounds. The results are very close to being indistinguishable, which was not the case for previous works that created false intersections where hair strands would erroneously go through solid objects. We can also stroke bunnies with our hair models in this truly amazing piece of work. ### Hairy Ball [2:43] These episodes are also available in early access for our Patreon supporters. We also have plenty of other really neat perks, I've put a link in the description box, make sure to have a look! Thanks for watching, and for your generous support, and I'll see you next time!