{"user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","date_created":"2018-12-11T11:50:16Z","oa_version":"Published Version","oa":1,"publisher":"Institute of Science and Technology Austria","status":"public","related_material":{"record":[{"status":"public","relation":"other","id":"5558"}]},"title":"Tracking, correcting and absorbing water surface waves","alternative_title":["ISTA Thesis"],"degree_awarded":"PhD","day":"15","type":"dissertation","file":[{"file_name":"IST-2016-640-v1+1_2016_Bojsen-Hansen_TCaAWSW.pdf","creator":"system","access_level":"open_access","content_type":"application/pdf","relation":"main_file","file_size":13869345,"date_created":"2018-12-12T10:13:02Z","file_id":"4982","date_updated":"2018-12-12T10:13:02Z"}],"date_updated":"2024-02-21T13:50:48Z","tmp":{"image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)","legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode"},"month":"07","article_processing_charge":"No","supervisor":[{"last_name":"Wojtan","first_name":"Christopher J","full_name":"Wojtan, Christopher J","id":"3C61F1D2-F248-11E8-B48F-1D18A9856A87","orcid":"0000-0001-6646-5546"}],"publication_status":"published","date_published":"2016-07-15T00:00:00Z","abstract":[{"lang":"eng","text":"Computer graphics is an extremely exciting field for two reasons. On the one hand,\r\nthere is a healthy injection of pragmatism coming from the visual effects industry\r\nthat want robust algorithms that work so they can produce results at an increasingly\r\nfrantic pace. On the other hand, they must always try to push the envelope and\r\nachieve the impossible to wow their audiences in the next blockbuster, which means\r\nthat the industry has not succumb to conservatism, and there is plenty of room to\r\ntry out new and crazy ideas if there is a chance that it will pan into something\r\nuseful.\r\nWater simulation has been in visual effects for decades, however it still remains\r\nextremely challenging because of its high computational cost and difficult artdirectability.\r\nThe work in this thesis tries to address some of these difficulties.\r\nSpecifically, we make the following three novel contributions to the state-of-the-art\r\nin water simulation for visual effects.\r\nFirst, we develop the first algorithm that can convert any sequence of closed\r\nsurfaces in time into a moving triangle mesh. State-of-the-art methods at the time\r\ncould only handle surfaces with fixed connectivity, but we are the first to be able to\r\nhandle surfaces that merge and split apart. This is important for water simulation\r\npractitioners, because it allows them to convert splashy water surfaces extracted\r\nfrom particles or simulated using grid-based level sets into triangle meshes that can\r\nbe either textured and enhanced with extra surface dynamics as a post-process.\r\nWe also apply our algorithm to other phenomena that merge and split apart, such\r\nas morphs and noisy reconstructions of human performances.\r\nSecond, we formulate a surface-based energy that measures the deviation of a\r\nwater surface froma physically valid state. Such discrepancies arise when there is a\r\nmismatch in the degrees of freedom between the water surface and the underlying\r\nphysics solver. This commonly happens when practitioners use a moving triangle\r\nmesh with a grid-based physics solver, or when high-resolution grid-based surfaces\r\nare combined with low-resolution physics. Following the direction of steepest\r\ndescent on our surface-based energy, we can either smooth these artifacts or turn\r\nthem into high-resolution waves by interpreting the energy as a physical potential.\r\nThird, we extend state-of-the-art techniques in non-reflecting boundaries to handle spatially and time-varying background flows. This allows a novel new\r\nworkflow where practitioners can re-simulate part of an existing simulation, such\r\nas removing a solid obstacle, adding a new splash or locally changing the resolution.\r\nSuch changes can easily lead to new waves in the re-simulated region that would\r\nreflect off of the new simulation boundary, effectively ruining the illusion of a\r\nseamless simulation boundary between the existing and new simulations. Our\r\nnon-reflecting boundaries makes sure that such waves are absorbed."}],"department":[{"_id":"ChWo"}],"publist_id":"6238","year":"2016","file_date_updated":"2018-12-12T10:13:02Z","acknowledgement":"First and foremost I would like to thank Chris. I have been incredibly lucky to have\r\nyou as my advisor. Your integrity and aspiration to do the right thing in all walks of\r\nlife is something I admire and aspire to. I also really appreciate the fact that when\r\nworking with you it felt like we were equals. I think we had a very synergetic work\r\nrelationship: I learned immensely from you, but I dare say that you learned a few\r\nthings from me as well. ;)\r\nNext, I would like to thank my amazing committee. Hao, it was a fantastic\r\nexperience working with you. You showed me how to persevere and keep morale\r\nhigh when things were looking the most bleak before the deadline. You are an\r\nincredible motivator and super fun to be around! Vladimir, thanks for the shared\r\nlunches and the poker games. Sorry for not bringing them back when I got busy.\r\nAlso, sorry for embarrassing you by asking about your guitar playing that one\r\ntime. You really are quite awesome! Nils, one of the friendliest and most humble\r\npeople you will meet and a top notch researcher to boot! Thank you for joining\r\nmy committee late!\r\nI would also like to acknowledge the Visual Computing group at IST Austria\r\nfrom whom I have learned so much. The excellent discussions we had in reading\r\ngroups and research meetings really helped me become a better researcher!\r\nNext, I would like to thank all the amazing people that I met during my PhD\r\nstudies, both at IST Austria, in Vienna and elsewhere. ","ddc":["004","005","006","532","621"],"author":[{"full_name":"Bojsen-Hansen, Morten","id":"439F0C8C-F248-11E8-B48F-1D18A9856A87","first_name":"Morten","last_name":"Bojsen-Hansen","orcid":"0000-0002-4417-3224"}],"has_accepted_license":"1","doi":"10.15479/AT:ISTA:th_640","page":"114","publication_identifier":{"issn":["2663-337X"]},"citation":{"ieee":"M. Bojsen-Hansen, “Tracking, correcting and absorbing water surface waves,” Institute of Science and Technology Austria, 2016.","mla":"Bojsen-Hansen, Morten. <i>Tracking, Correcting and Absorbing Water Surface Waves</i>. Institute of Science and Technology Austria, 2016, doi:<a href=\"https://doi.org/10.15479/AT:ISTA:th_640\">10.15479/AT:ISTA:th_640</a>.","short":"M. Bojsen-Hansen, Tracking, Correcting and Absorbing Water Surface Waves, Institute of Science and Technology Austria, 2016.","ama":"Bojsen-Hansen M. Tracking, correcting and absorbing water surface waves. 2016. doi:<a href=\"https://doi.org/10.15479/AT:ISTA:th_640\">10.15479/AT:ISTA:th_640</a>","chicago":"Bojsen-Hansen, Morten. “Tracking, Correcting and Absorbing Water Surface Waves.” Institute of Science and Technology Austria, 2016. <a href=\"https://doi.org/10.15479/AT:ISTA:th_640\">https://doi.org/10.15479/AT:ISTA:th_640</a>.","ista":"Bojsen-Hansen M. 2016. Tracking, correcting and absorbing water surface waves. Institute of Science and Technology Austria.","apa":"Bojsen-Hansen, M. (2016). <i>Tracking, correcting and absorbing water surface waves</i>. Institute of Science and Technology Austria. <a href=\"https://doi.org/10.15479/AT:ISTA:th_640\">https://doi.org/10.15479/AT:ISTA:th_640</a>"},"_id":"1122","language":[{"iso":"eng"}]}