--- _id: '8535' abstract: - lang: eng text: We propose a method to enhance the visual detail of a water surface simulation. Our method works as a post-processing step which takes a simulation as input and increases its apparent resolution by simulating many detailed Lagrangian water waves on top of it. We extend linear water wave theory to work in non-planar domains which deform over time, and we discretize the theory using Lagrangian wave packets attached to spline curves. The method is numerically stable and trivially parallelizable, and it produces high frequency ripples with dispersive wave-like behaviors customized to the underlying fluid simulation. acknowledged_ssus: - _id: ScienComp acknowledgement: We wish to thank the anonymous reviewers and the members of the Visual Computing Group at IST Austria for their valuable feedback. This research was supported by the Scientific Service Units (SSU) of IST Austria through resources provided by Scientific Computing. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 638176 and Marie SkłodowskaCurie Grant Agreement No. 665385. article_number: '65' article_processing_charge: No article_type: original author: - first_name: Tomas full_name: Skrivan, Tomas id: 486A5A46-F248-11E8-B48F-1D18A9856A87 last_name: Skrivan - first_name: Andreas full_name: Soderstrom, Andreas last_name: Soderstrom - first_name: John full_name: Johansson, John last_name: Johansson - first_name: Christoph full_name: Sprenger, Christoph last_name: Sprenger - first_name: Ken full_name: Museth, Ken last_name: Museth - 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: 'Skrivan T, Soderstrom A, Johansson J, Sprenger C, Museth K, Wojtan C. Wave curves: Simulating Lagrangian water waves on dynamically deforming surfaces. ACM Transactions on Graphics. 2020;39(4). doi:10.1145/3386569.3392466' apa: 'Skrivan, T., Soderstrom, A., Johansson, J., Sprenger, C., Museth, K., & Wojtan, C. (2020). Wave curves: Simulating Lagrangian water waves on dynamically deforming surfaces. ACM Transactions on Graphics. Association for Computing Machinery. https://doi.org/10.1145/3386569.3392466' chicago: 'Skrivan, Tomas, Andreas Soderstrom, John Johansson, Christoph Sprenger, Ken Museth, and Chris Wojtan. “Wave Curves: Simulating Lagrangian Water Waves on Dynamically Deforming Surfaces.” ACM Transactions on Graphics. Association for Computing Machinery, 2020. https://doi.org/10.1145/3386569.3392466.' ieee: 'T. Skrivan, A. Soderstrom, J. Johansson, C. Sprenger, K. Museth, and C. Wojtan, “Wave curves: Simulating Lagrangian water waves on dynamically deforming surfaces,” ACM Transactions on Graphics, vol. 39, no. 4. Association for Computing Machinery, 2020.' ista: 'Skrivan T, Soderstrom A, Johansson J, Sprenger C, Museth K, Wojtan C. 2020. Wave curves: Simulating Lagrangian water waves on dynamically deforming surfaces. ACM Transactions on Graphics. 39(4), 65.' mla: 'Skrivan, Tomas, et al. “Wave Curves: Simulating Lagrangian Water Waves on Dynamically Deforming Surfaces.” ACM Transactions on Graphics, vol. 39, no. 4, 65, Association for Computing Machinery, 2020, doi:10.1145/3386569.3392466.' short: T. Skrivan, A. Soderstrom, J. Johansson, C. Sprenger, K. Museth, C. Wojtan, ACM Transactions on Graphics 39 (2020). date_created: 2020-09-20T22:01:37Z date_published: 2020-07-08T00:00:00Z date_updated: 2023-08-22T09:28:27Z day: '08' ddc: - '000' department: - _id: ChWo doi: 10.1145/3386569.3392466 ec_funded: 1 external_id: isi: - '000583700300038' file: - access_level: open_access checksum: c3a680893f01cc4a9e961ff0a4cfa12f content_type: application/pdf creator: dernst date_created: 2020-09-21T07:51:44Z date_updated: 2020-09-21T07:51:44Z file_id: '8541' file_name: 2020_ACM_Skrivan.pdf file_size: 20223953 relation: main_file success: 1 file_date_updated: 2020-09-21T07:51:44Z has_accepted_license: '1' intvolume: ' 39' isi: 1 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 - _id: 2564DBCA-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '665385' name: International IST Doctoral Program publication: ACM Transactions on Graphics publication_identifier: eissn: - '15577368' issn: - '07300301' publication_status: published publisher: Association for Computing Machinery quality_controlled: '1' scopus_import: '1' status: public title: 'Wave curves: Simulating Lagrangian water waves on dynamically deforming surfaces' type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 39 year: '2020' ... --- _id: '7002' abstract: - lang: eng text: Multiple Importance Sampling (MIS) is a key technique for achieving robustness of Monte Carlo estimators in computer graphics and other fields. We derive optimal weighting functions for MIS that provably minimize the variance of an MIS estimator, given a set of sampling techniques. We show that the resulting variance reduction over the balance heuristic can be higher than predicted by the variance bounds derived by Veach and Guibas, who assumed only non-negative weights in their proof. We theoretically analyze the variance of the optimal MIS weights and show the relation to the variance of the balance heuristic. Furthermore, we establish a connection between the new weighting functions and control variates as previously applied to mixture sampling. We apply the new optimal weights to integration problems in light transport and show that they allow for new design considerations when choosing the appropriate sampling techniques for a given integration problem. article_number: '37' article_processing_charge: No article_type: original author: - first_name: Ivo full_name: Kondapaneni, Ivo last_name: Kondapaneni - first_name: Petr full_name: Vevoda, Petr last_name: Vevoda - first_name: Pascal full_name: Grittmann, Pascal last_name: Grittmann - first_name: Tomas full_name: Skrivan, Tomas id: 486A5A46-F248-11E8-B48F-1D18A9856A87 last_name: Skrivan - first_name: Philipp full_name: Slusallek, Philipp last_name: Slusallek - first_name: Jaroslav full_name: Křivánek, Jaroslav last_name: Křivánek citation: ama: Kondapaneni I, Vevoda P, Grittmann P, Skrivan T, Slusallek P, Křivánek J. Optimal multiple importance sampling. ACM Transactions on Graphics. 2019;38(4). doi:10.1145/3306346.3323009 apa: Kondapaneni, I., Vevoda, P., Grittmann, P., Skrivan, T., Slusallek, P., & Křivánek, J. (2019). Optimal multiple importance sampling. ACM Transactions on Graphics. ACM. https://doi.org/10.1145/3306346.3323009 chicago: Kondapaneni, Ivo, Petr Vevoda, Pascal Grittmann, Tomas Skrivan, Philipp Slusallek, and Jaroslav Křivánek. “Optimal Multiple Importance Sampling.” ACM Transactions on Graphics. ACM, 2019. https://doi.org/10.1145/3306346.3323009. ieee: I. Kondapaneni, P. Vevoda, P. Grittmann, T. Skrivan, P. Slusallek, and J. Křivánek, “Optimal multiple importance sampling,” ACM Transactions on Graphics, vol. 38, no. 4. ACM, 2019. ista: Kondapaneni I, Vevoda P, Grittmann P, Skrivan T, Slusallek P, Křivánek J. 2019. Optimal multiple importance sampling. ACM Transactions on Graphics. 38(4), 37. mla: Kondapaneni, Ivo, et al. “Optimal Multiple Importance Sampling.” ACM Transactions on Graphics, vol. 38, no. 4, 37, ACM, 2019, doi:10.1145/3306346.3323009. short: I. Kondapaneni, P. Vevoda, P. Grittmann, T. Skrivan, P. Slusallek, J. Křivánek, ACM Transactions on Graphics 38 (2019). date_created: 2019-11-12T13:05:40Z date_published: 2019-07-01T00:00:00Z date_updated: 2023-08-30T07:21:25Z day: '01' department: - _id: ChWo doi: 10.1145/3306346.3323009 ec_funded: 1 external_id: isi: - '000475740600011' intvolume: ' 38' isi: 1 issue: '4' language: - iso: eng month: '07' oa_version: None project: - _id: 2508E324-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '642841' name: Distributed 3D Object Design publication: ACM Transactions on Graphics publication_identifier: issn: - 0730-0301 publication_status: published publisher: ACM quality_controlled: '1' scopus_import: '1' status: public title: Optimal multiple importance sampling type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 38 year: '2019' ... --- _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: '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' ...