---
_id: '7418'
abstract:
- lang: eng
text: Multiple importance sampling (MIS) has become an indispensable tool in Monte
Carlo rendering, widely accepted as a near-optimal solution for combining different
sampling techniques. But an MIS combination, using the common balance or power
heuristics, often results in an overly defensive estimator, leading to high variance.
We show that by generalizing the MIS framework, variance can be substantially
reduced. Specifically, we optimize one of the combined sampling techniques so
as to decrease the overall variance of the resulting MIS estimator. We apply the
approach to the computation of direct illumination due to an HDR environment map
and to the computation of global illumination using a path guiding algorithm.
The implementation can be as simple as subtracting a constant value from the tabulated
sampling density done entirely in a preprocessing step. This produces a consistent
noise reduction in all our tests with no negative influence on run time, no artifacts
or bias, and no failure cases.
article_number: '151'
article_processing_charge: No
article_type: original
author:
- first_name: Ondřej
full_name: Karlík, Ondřej
last_name: Karlík
- first_name: Martin
full_name: Šik, Martin
last_name: Šik
- first_name: Petr
full_name: Vévoda, Petr
last_name: Vévoda
- first_name: Tomas
full_name: Skrivan, Tomas
id: 486A5A46-F248-11E8-B48F-1D18A9856A87
last_name: Skrivan
- first_name: Jaroslav
full_name: Křivánek, Jaroslav
last_name: Křivánek
citation:
ama: 'Karlík O, Šik M, Vévoda P, Skrivan T, Křivánek J. MIS compensation: Optimizing
sampling techniques in multiple importance sampling. ACM Transactions on Graphics.
2019;38(6). doi:10.1145/3355089.3356565'
apa: 'Karlík, O., Šik, M., Vévoda, P., Skrivan, T., & Křivánek, J. (2019). MIS
compensation: Optimizing sampling techniques in multiple importance sampling.
ACM Transactions on Graphics. ACM. https://doi.org/10.1145/3355089.3356565'
chicago: 'Karlík, Ondřej, Martin Šik, Petr Vévoda, Tomas Skrivan, and Jaroslav Křivánek.
“MIS Compensation: Optimizing Sampling Techniques in Multiple Importance Sampling.”
ACM Transactions on Graphics. ACM, 2019. https://doi.org/10.1145/3355089.3356565.'
ieee: 'O. Karlík, M. Šik, P. Vévoda, T. Skrivan, and J. Křivánek, “MIS compensation:
Optimizing sampling techniques in multiple importance sampling,” ACM Transactions
on Graphics, vol. 38, no. 6. ACM, 2019.'
ista: 'Karlík O, Šik M, Vévoda P, Skrivan T, Křivánek J. 2019. MIS compensation:
Optimizing sampling techniques in multiple importance sampling. ACM Transactions
on Graphics. 38(6), 151.'
mla: 'Karlík, Ondřej, et al. “MIS Compensation: Optimizing Sampling Techniques in
Multiple Importance Sampling.” ACM Transactions on Graphics, vol. 38, no.
6, 151, ACM, 2019, doi:10.1145/3355089.3356565.'
short: O. Karlík, M. Šik, P. Vévoda, T. Skrivan, J. Křivánek, ACM Transactions on
Graphics 38 (2019).
date_created: 2020-01-30T10:19:43Z
date_published: 2019-11-01T00:00:00Z
date_updated: 2023-09-06T15:22:23Z
day: '01'
department:
- _id: ChWo
doi: 10.1145/3355089.3356565
external_id:
isi:
- '000498397300001'
intvolume: ' 38'
isi: 1
issue: '6'
language:
- iso: eng
month: '11'
oa_version: None
publication: ACM Transactions on Graphics
publication_identifier:
eissn:
- 1557-7368
issn:
- 0730-0301
publication_status: published
publisher: ACM
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'MIS compensation: Optimizing sampling techniques in multiple importance sampling'
type: journal_article
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 38
year: '2019'
...
---
_id: '6642'
abstract:
- lang: eng
text: We present a thermodynamically based approach to the design of models for
viscoelastic fluids with stress diffusion effect. In particular, we show how to
add a stress diffusion term to some standard viscoelastic rate-type models (Giesekus,
FENE-P, Johnson–Segalman, Phan-Thien–Tanner and Bautista–Manero–Puig) so that
the resulting models with the added stress diffusion term are thermodynamically
consistent in the sense that they obey the first and the second law of thermodynamics.
We point out the potential applications of the provided thermodynamical background
in the study of flows of fluids described by the proposed models.
article_number: '020002'
article_processing_charge: No
author:
- first_name: Mark
full_name: Dostalík, Mark
last_name: Dostalík
- first_name: Vít
full_name: Pruša, Vít
last_name: Pruša
- first_name: Tomas
full_name: Skrivan, Tomas
id: 486A5A46-F248-11E8-B48F-1D18A9856A87
last_name: Skrivan
citation:
ama: 'Dostalík M, Pruša V, Skrivan T. On diffusive variants of some classical viscoelastic
rate-type models. In: AIP Conference Proceedings. Vol 2107. AIP Publishing;
2019. doi:10.1063/1.5109493'
apa: 'Dostalík, M., Pruša, V., & Skrivan, T. (2019). On diffusive variants of
some classical viscoelastic rate-type models. In AIP Conference Proceedings
(Vol. 2107). Zlin, Czech Republic: AIP Publishing. https://doi.org/10.1063/1.5109493'
chicago: Dostalík, Mark, Vít Pruša, and Tomas Skrivan. “On Diffusive Variants of
Some Classical Viscoelastic Rate-Type Models.” In AIP Conference Proceedings,
Vol. 2107. AIP Publishing, 2019. https://doi.org/10.1063/1.5109493.
ieee: M. Dostalík, V. Pruša, and T. Skrivan, “On diffusive variants of some classical
viscoelastic rate-type models,” in AIP Conference Proceedings, Zlin, Czech
Republic, 2019, vol. 2107.
ista: Dostalík M, Pruša V, Skrivan T. 2019. On diffusive variants of some classical
viscoelastic rate-type models. AIP Conference Proceedings. 8th International Conference
on Novel Trends in Rheology vol. 2107, 020002.
mla: Dostalík, Mark, et al. “On Diffusive Variants of Some Classical Viscoelastic
Rate-Type Models.” AIP Conference Proceedings, vol. 2107, 020002, AIP Publishing,
2019, doi:10.1063/1.5109493.
short: M. Dostalík, V. Pruša, T. Skrivan, in:, AIP Conference Proceedings, AIP Publishing,
2019.
conference:
end_date: 2019-07-31
location: Zlin, Czech Republic
name: 8th International Conference on Novel Trends in Rheology
start_date: 2019-07-30
date_created: 2019-07-15T10:07:09Z
date_published: 2019-05-21T00:00:00Z
date_updated: 2024-02-28T13:01:28Z
day: '21'
department:
- _id: ChWo
doi: 10.1063/1.5109493
external_id:
arxiv:
- '1902.07983'
isi:
- '000479303100002'
intvolume: ' 2107'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1902.07983
month: '05'
oa: 1
oa_version: Preprint
publication: AIP Conference Proceedings
publication_status: published
publisher: AIP Publishing
quality_controlled: '1'
scopus_import: '1'
status: public
title: On diffusive variants of some classical viscoelastic rate-type models
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 2107
year: '2019'
...
---
_id: '135'
abstract:
- lang: eng
text: The Fluid Implicit Particle method (FLIP) reduces numerical dissipation by
combining particles with grids. To improve performance, the subsequent narrow
band FLIP method (NB‐FLIP) uses a FLIP‐based fluid simulation only near the liquid
surface and a traditional grid‐based fluid simulation away from the surface. This
spatially‐limited FLIP simulation significantly reduces the number of particles
and alleviates a computational bottleneck. In this paper, we extend the NB‐FLIP
idea even further, by allowing a simulation to transition between a FLIP‐like
fluid simulation and a grid‐based simulation in arbitrary locations, not just
near the surface. This approach leads to even more savings in memory and computation,
because we can concentrate the particles only in areas where they are needed.
More importantly, this new method allows us to seamlessly transition to smooth
implicit surface geometry wherever the particle‐based simulation is unnecessary.
Consequently, our method leads to a practical algorithm for avoiding the noisy
surface artifacts associated with particle‐based liquid simulations, while simultaneously
maintaining the benefits of a FLIP simulation in regions of dynamic motion.
alternative_title:
- Eurographics
article_processing_charge: No
article_type: original
author:
- first_name: Takahiro
full_name: Sato, Takahiro
last_name: Sato
- first_name: Christopher J
full_name: Wojtan, Christopher J
id: 3C61F1D2-F248-11E8-B48F-1D18A9856A87
last_name: Wojtan
orcid: 0000-0001-6646-5546
- first_name: Nils
full_name: Thuerey, Nils
last_name: Thuerey
- first_name: Takeo
full_name: Igarashi, Takeo
last_name: Igarashi
- first_name: Ryoichi
full_name: Ando, Ryoichi
last_name: Ando
citation:
ama: Sato T, Wojtan C, Thuerey N, Igarashi T, Ando R. Extended narrow band FLIP
for liquid simulations. Computer Graphics Forum. 2018;37(2):169-177. doi:10.1111/cgf.13351
apa: Sato, T., Wojtan, C., Thuerey, N., Igarashi, T., & Ando, R. (2018). Extended
narrow band FLIP for liquid simulations. Computer Graphics Forum. Wiley.
https://doi.org/10.1111/cgf.13351
chicago: Sato, Takahiro, Chris Wojtan, Nils Thuerey, Takeo Igarashi, and Ryoichi
Ando. “Extended Narrow Band FLIP for Liquid Simulations.” Computer Graphics
Forum. Wiley, 2018. https://doi.org/10.1111/cgf.13351.
ieee: T. Sato, C. Wojtan, N. Thuerey, T. Igarashi, and R. Ando, “Extended narrow
band FLIP for liquid simulations,” Computer Graphics Forum, vol. 37, no.
2. Wiley, pp. 169–177, 2018.
ista: Sato T, Wojtan C, Thuerey N, Igarashi T, Ando R. 2018. Extended narrow band
FLIP for liquid simulations. Computer Graphics Forum. 37(2), 169–177.
mla: Sato, Takahiro, et al. “Extended Narrow Band FLIP for Liquid Simulations.”
Computer Graphics Forum, vol. 37, no. 2, Wiley, 2018, pp. 169–77, doi:10.1111/cgf.13351.
short: T. Sato, C. Wojtan, N. Thuerey, T. Igarashi, R. Ando, Computer Graphics Forum
37 (2018) 169–177.
date_created: 2018-12-11T11:44:49Z
date_published: 2018-05-22T00:00:00Z
date_updated: 2023-09-11T14:00:26Z
day: '22'
ddc:
- '006'
department:
- _id: ChWo
doi: 10.1111/cgf.13351
ec_funded: 1
external_id:
isi:
- '000434085600016'
file:
- access_level: open_access
checksum: 8edb90da8a72395eb5d970580e0925b6
content_type: application/pdf
creator: wojtan
date_created: 2020-10-08T08:38:23Z
date_updated: 2020-10-08T08:38:23Z
file_id: '8627'
file_name: exnbflip.pdf
file_size: 54309947
relation: main_file
success: 1
file_date_updated: 2020-10-08T08:38:23Z
has_accepted_license: '1'
intvolume: ' 37'
isi: 1
issue: '2'
language:
- iso: eng
month: '05'
oa: 1
oa_version: Submitted Version
page: 169 - 177
project:
- _id: 2533E772-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '638176'
name: Efficient Simulation of Natural Phenomena at Extremely Large Scales
publication: Computer Graphics Forum
publication_identifier:
issn:
- 0167-7055
publication_status: published
publisher: Wiley
quality_controlled: '1'
scopus_import: '1'
status: public
title: Extended narrow band FLIP for liquid simulations
type: journal_article
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 37
year: '2018'
...
---
_id: '134'
abstract:
- lang: eng
text: "The current state of the art in real-time two-dimensional water wave simulation
requires developers to choose between efficient Fourier-based methods, which lack
interactions with moving obstacles, and finite-difference or finite element methods,
which handle environmental interactions but are significantly more expensive.
This paper attempts to bridge this long-standing gap between complexity and performance,
by proposing a new wave simulation method that can faithfully simulate wave interactions
with moving obstacles in real time while simultaneously preserving minute details
and accommodating very large simulation domains.\r\n\r\nPrevious methods for simulating
2D water waves directly compute the change in height of the water surface, a strategy
which imposes limitations based on the CFL condition (fast moving waves require
small time steps) and Nyquist's limit (small wave details require closely-spaced
simulation variables). This paper proposes a novel wavelet transformation that
discretizes the liquid motion in terms of amplitude-like functions that vary over
space, frequency, and direction, effectively generalizing Fourier-based methods
to handle local interactions. Because these new variables change much more slowly
over space than the original water height function, our change of variables drastically
reduces the limitations of the CFL condition and Nyquist limit, allowing us to
simulate highly detailed water waves at very large visual resolutions. Our discretization
is amenable to fast summation and easy to parallelize. We also present basic extensions
like pre-computed wave paths and two-way solid fluid coupling. Finally, we argue
that our discretization provides a convenient set of variables for artistic manipulation,
which we illustrate with a novel wave-painting interface."
acknowledged_ssus:
- _id: ScienComp
alternative_title:
- SIGGRAPH
article_number: '94'
article_processing_charge: No
author:
- first_name: Stefan
full_name: Jeschke, Stefan
id: 44D6411A-F248-11E8-B48F-1D18A9856A87
last_name: Jeschke
- first_name: Tomas
full_name: Skrivan, Tomas
id: 486A5A46-F248-11E8-B48F-1D18A9856A87
last_name: Skrivan
- first_name: Matthias
full_name: Mueller Fischer, Matthias
last_name: Mueller Fischer
- first_name: Nuttapong
full_name: Chentanez, Nuttapong
last_name: Chentanez
- first_name: Miles
full_name: Macklin, Miles
last_name: Macklin
- first_name: Christopher J
full_name: Wojtan, Christopher J
id: 3C61F1D2-F248-11E8-B48F-1D18A9856A87
last_name: Wojtan
orcid: 0000-0001-6646-5546
citation:
ama: Jeschke S, Skrivan T, Mueller Fischer M, Chentanez N, Macklin M, Wojtan C.
Water surface wavelets. ACM Transactions on Graphics. 2018;37(4). doi:10.1145/3197517.3201336
apa: Jeschke, S., Skrivan, T., Mueller Fischer, M., Chentanez, N., Macklin, M.,
& Wojtan, C. (2018). Water surface wavelets. ACM Transactions on Graphics.
ACM. https://doi.org/10.1145/3197517.3201336
chicago: Jeschke, Stefan, Tomas Skrivan, Matthias Mueller Fischer, Nuttapong Chentanez,
Miles Macklin, and Chris Wojtan. “Water Surface Wavelets.” ACM Transactions
on Graphics. ACM, 2018. https://doi.org/10.1145/3197517.3201336.
ieee: S. Jeschke, T. Skrivan, M. Mueller Fischer, N. Chentanez, M. Macklin, and
C. Wojtan, “Water surface wavelets,” ACM Transactions on Graphics, vol.
37, no. 4. ACM, 2018.
ista: Jeschke S, Skrivan T, Mueller Fischer M, Chentanez N, Macklin M, Wojtan C.
2018. Water surface wavelets. ACM Transactions on Graphics. 37(4), 94.
mla: Jeschke, Stefan, et al. “Water Surface Wavelets.” ACM Transactions on Graphics,
vol. 37, no. 4, 94, ACM, 2018, doi:10.1145/3197517.3201336.
short: S. Jeschke, T. Skrivan, M. Mueller Fischer, N. Chentanez, M. Macklin, C.
Wojtan, ACM Transactions on Graphics 37 (2018).
date_created: 2018-12-11T11:44:48Z
date_published: 2018-07-30T00:00:00Z
date_updated: 2024-02-28T13:58:51Z
day: '30'
ddc:
- '000'
department:
- _id: ChWo
doi: 10.1145/3197517.3201336
ec_funded: 1
external_id:
isi:
- '000448185000055'
file:
- access_level: open_access
checksum: db75ebabe2ec432bf41389e614d6ef62
content_type: application/pdf
creator: dernst
date_created: 2018-12-18T09:59:23Z
date_updated: 2020-07-14T12:44:45Z
file_id: '5744'
file_name: 2018_ACM_Jeschke.pdf
file_size: 22185016
relation: main_file
file_date_updated: 2020-07-14T12:44:45Z
has_accepted_license: '1'
intvolume: ' 37'
isi: 1
issue: '4'
language:
- iso: eng
license: https://creativecommons.org/licenses/by-nc-sa/4.0/
month: '07'
oa: 1
oa_version: Published Version
project:
- _id: 2533E772-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '638176'
name: Efficient Simulation of Natural Phenomena at Extremely Large Scales
- _id: 2564DBCA-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '665385'
name: International IST Doctoral Program
publication: ACM Transactions on Graphics
publication_status: published
publisher: ACM
publist_id: '7789'
quality_controlled: '1'
related_material:
link:
- description: News on IST Homepage
relation: press_release
url: https://ist.ac.at/en/news/new-water-simulation-captures-small-details-even-in-large-scenes/
scopus_import: '1'
status: public
title: Water surface wavelets
tmp:
image: /images/cc_by_nc_sa.png
legal_code_url: https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode
name: Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC
BY-NC-SA 4.0)
short: CC BY-NC-SA (4.0)
type: journal_article
user_id: 2EBD1598-F248-11E8-B48F-1D18A9856A87
volume: 37
year: '2018'
...
---
_id: '470'
abstract:
- lang: eng
text: This paper presents a method for simulating water surface waves as a displacement
field on a 2D domain. Our method relies on Lagrangian particles that carry packets
of water wave energy; each packet carries information about an entire group of
wave trains, as opposed to only a single wave crest. Our approach is unconditionally
stable and can simulate high resolution geometric details. This approach also
presents a straightforward interface for artistic control, because it is essentially
a particle system with intuitive parameters like wavelength and amplitude. Our
implementation parallelizes well and runs in real time for moderately challenging
scenarios.
acknowledged_ssus:
- _id: ScienComp
article_number: '103'
article_processing_charge: Yes (in subscription journal)
article_type: original
author:
- first_name: Stefan
full_name: Jeschke, Stefan
id: 44D6411A-F248-11E8-B48F-1D18A9856A87
last_name: Jeschke
- first_name: Christopher J
full_name: Wojtan, Christopher J
id: 3C61F1D2-F248-11E8-B48F-1D18A9856A87
last_name: Wojtan
orcid: 0000-0001-6646-5546
citation:
ama: Jeschke S, Wojtan C. Water wave packets. ACM Transactions on Graphics.
2017;36(4). doi:10.1145/3072959.3073678
apa: Jeschke, S., & Wojtan, C. (2017). Water wave packets. ACM Transactions
on Graphics. ACM. https://doi.org/10.1145/3072959.3073678
chicago: Jeschke, Stefan, and Chris Wojtan. “Water Wave Packets.” ACM Transactions
on Graphics. ACM, 2017. https://doi.org/10.1145/3072959.3073678.
ieee: S. Jeschke and C. Wojtan, “Water wave packets,” ACM Transactions on Graphics,
vol. 36, no. 4. ACM, 2017.
ista: Jeschke S, Wojtan C. 2017. Water wave packets. ACM Transactions on Graphics.
36(4), 103.
mla: Jeschke, Stefan, and Chris Wojtan. “Water Wave Packets.” ACM Transactions
on Graphics, vol. 36, no. 4, 103, ACM, 2017, doi:10.1145/3072959.3073678.
short: S. Jeschke, C. Wojtan, ACM Transactions on Graphics 36 (2017).
date_created: 2018-12-11T11:46:39Z
date_published: 2017-07-01T00:00:00Z
date_updated: 2023-02-23T12:20:26Z
day: '01'
ddc:
- '006'
department:
- _id: ChWo
doi: 10.1145/3072959.3073678
ec_funded: 1
file:
- access_level: open_access
checksum: 82a3b2bfeee4ddef16ecc21675d1a48a
content_type: application/pdf
creator: wojtan
date_created: 2020-01-24T09:32:35Z
date_updated: 2020-07-14T12:46:34Z
file_id: '7359'
file_name: wavepackets_final.pdf
file_size: 13131683
relation: main_file
file_date_updated: 2020-07-14T12:46:34Z
has_accepted_license: '1'
intvolume: ' 36'
issue: '4'
language:
- iso: eng
month: '07'
oa: 1
oa_version: Published Version
project:
- _id: 2533E772-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '638176'
name: Efficient Simulation of Natural Phenomena at Extremely Large Scales
publication: ACM Transactions on Graphics
publication_identifier:
issn:
- '07300301'
publication_status: published
publisher: ACM
publist_id: '7350'
quality_controlled: '1'
scopus_import: 1
status: public
title: Water wave packets
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 36
year: '2017'
...