---
_id: '1122'
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."
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. "
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Morten
full_name: Bojsen-Hansen, Morten
id: 439F0C8C-F248-11E8-B48F-1D18A9856A87
last_name: Bojsen-Hansen
orcid: 0000-0002-4417-3224
citation:
ama: Bojsen-Hansen M. Tracking, correcting and absorbing water surface waves. 2016.
doi:10.15479/AT:ISTA:th_640
apa: Bojsen-Hansen, M. (2016). Tracking, correcting and absorbing water surface
waves. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:th_640
chicago: Bojsen-Hansen, Morten. “Tracking, Correcting and Absorbing Water Surface
Waves.” Institute of Science and Technology Austria, 2016. https://doi.org/10.15479/AT:ISTA:th_640.
ieee: M. Bojsen-Hansen, “Tracking, correcting and absorbing water surface waves,”
Institute of Science and Technology Austria, 2016.
ista: Bojsen-Hansen M. 2016. Tracking, correcting and absorbing water surface waves.
Institute of Science and Technology Austria.
mla: Bojsen-Hansen, Morten. Tracking, Correcting and Absorbing Water Surface
Waves. Institute of Science and Technology Austria, 2016, doi:10.15479/AT:ISTA:th_640.
short: M. Bojsen-Hansen, Tracking, Correcting and Absorbing Water Surface Waves,
Institute of Science and Technology Austria, 2016.
date_created: 2018-12-11T11:50:16Z
date_published: 2016-07-15T00:00:00Z
date_updated: 2024-02-21T13:50:48Z
day: '15'
ddc:
- '004'
- '005'
- '006'
- '532'
- '621'
degree_awarded: PhD
department:
- _id: ChWo
doi: 10.15479/AT:ISTA:th_640
file:
- access_level: open_access
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:13:02Z
date_updated: 2018-12-12T10:13:02Z
file_id: '4982'
file_name: IST-2016-640-v1+1_2016_Bojsen-Hansen_TCaAWSW.pdf
file_size: 13869345
relation: main_file
file_date_updated: 2018-12-12T10:13:02Z
has_accepted_license: '1'
language:
- iso: eng
month: '07'
oa: 1
oa_version: Published Version
page: '114'
publication_identifier:
issn:
- 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
publist_id: '6238'
related_material:
record:
- id: '5558'
relation: other
status: public
status: public
supervisor:
- first_name: Christopher J
full_name: Wojtan, Christopher J
id: 3C61F1D2-F248-11E8-B48F-1D18A9856A87
last_name: Wojtan
orcid: 0000-0001-6646-5546
title: Tracking, correcting and absorbing water surface waves
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: dissertation
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
year: '2016'
...