检索结果-内蒙古大学图书馆

Latent-space Dynamics for Reduced Deformable simulation

COMPUTER GRAPHICS FORUM 2019年第2期38卷 379-391页

作者： Fulton, Lawson Modi, Vismay Duvenaud, David Levin, David I. W. Jacobson, Alec Univ Toronto Toronto ON Canada

We propose the first reduced model simulation framework for deformable solid dynamics using autoencoder neural networks. We provide a data-driven approach to generating nonlinear reduced spaces for deformation dynamics. In contrast to previous methods using machine learning which accelerate simulation by approximating the time-stepping function, we solve the true equations of motion in the latent-space using a variational formulation of implicit integration. Our approach produces drastically smaller reduced spaces than conventional linear model reduction, improving performance and robustness. Furthermore, our method works well with existing force-approximation cubature methods.

关键词： CCS Concepts •computing methodologies → physical simulation Dimensionality reduction and manifold learning

来源：评论

学校读者我要写书评

暂无评论

A CNN-based Flow Correction Method for Fast Preview

引用

COMPUTER GRAPHICS FORUM 2019年第2期38卷 431-440页

作者： Xiao, Xiangyun Wang, Hui Yang, Xubo Shanghai Jiao Tong Univ Sch Software Digital ART Lab Shanghai Peoples R China

Eulerian-based smoke simulations are sensitive to the initial parameters and grid resolutions. Due to the numerical dissipation on different levels of the grid and the nonlinearity of the governing equations, the differences in simulation resolutions will result in different results. This makes it challenging for artists to preview the animation results based on low-resolution simulations. In this paper, we propose a learning-based flow correction method for fast previewing based on low-resolution smoke simulations. The main components of our approach lie in a deep convolutional neural network, a grid-layer feature vector and a special loss function. We provide a novel matching model to represent the relationship between low-resolution and high-resolution smoke simulations and correct the overall shape of a low-resolution simulation to closely follow the shape of a high-resolution down-sampled version. We introduce the grid-layer concept to effectively represent the 3D fluid shape, which can also reduce the input and output dimensions. We design a special loss function for the fluid divergence-free constraint in the neural network training process. We have demonstrated the efficacy and the generality of our approach by simulating a diversity of animations deviating from the original training set. In addition, we have integrated our approach into an existing fluid simulation framework to showcase its wide applications.

关键词： CCS Concepts •computing methodologies → physical simulation Neural networks

来源：评论

学校读者我要写书评

暂无评论

Strain Rate Dissipation for Elastic Deformations

引用

COMPUTER GRAPHICS FORUM 2018年第8期37卷 161-170页

作者： Sanchez-Banderas, Rosa M. Otaduy, Miguel A. Univ Rey Juan Carlos Madrid Spain

Damping determines how the energy in dynamic deformations is dissipated. The design of damping requires models where the behavior along deformation modes is easily controlled, while other motions are left unaffected. In this paper, we propose a framework for the design of damping using dissipation potentials formulated as functions of strain rate. We study simple parameterizations of the models, the application to continuum and discrete deformation models, and practical implications for implementation. We also study previous simple damping models, in particular we demonstrate limitations of Rayleigh damping. We analyze in detail the application of strain rate dissipation potentials to two highly different deformation models, StVK hyperlasticity and yarn-level cloth with sliding persistent contacts. These deformation models are representative of the range of applicability of the damping model.

关键词： CCS Concepts •computing methodologies → physical simulation

来源：评论

学校读者我要写书评

暂无评论

Liquid Splash Modeling with Neural Networks

引用

COMPUTER GRAPHICS FORUM 2018年第8期37卷 171-182页

作者： Um, Kiwon Hu, Xiangyu Thuerey, Nils Tech Univ Munich Munich Germany

This paper proposes a new data-driven approach to model detailed splashes for liquid simulations with neural networks. Our model learns to generate small-scale splash detail for the fluid-implicit-particle method using training data acquired from physically parametrized, high resolution simulations. We use neural networks to model the regression of splash formation using a classifier together with a velocity modifier. For the velocity modification, we employ a heteroscedastic model. We evaluate our method for different spatial scales, simulation setups, and solvers. Our simulation results demonstrate that our model significantly improves visual fidelity with a large amount of realistic droplet formation and yields splash detail much more efficiently than finer discretizations.

关键词： CCS Concepts •computing methodologies → physical simulation Supervised learning by regression

来源：评论

学校读者我要写书评

暂无评论

Extended Narrow Band FLIP for Liquid simulations

引用

COMPUTER GRAPHICS FORUM 2018年第2期37卷 169-177页

作者： Sato, T. Wojtan, C. Thuerey, N. Igarashi, T. Ando, R. Univ Tokyo Tokyo Japan IST Austria Vienna Austria Tech Univ Munich Munich Germany Natl Inst Informat Tokyo Japan

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.

关键词： CCS Concepts •computing methodologies → physical simulation

来源：评论

学校读者我要写书评

暂无评论

Fast Corotated FEM using Operator Splitting

引用

COMPUTER GRAPHICS FORUM 2018年第8期37卷 149-160页

作者： Kugelstadt, T. Koschier, D. Bender, J. Rhein Westfal TH Aachen Aachen Germany UCL London England

In this paper we present a novel operator splitting approach for corotated FEM simulations. The deformation energy of the corotated linear material model consists of two additive terms. The first term models stretching in the individual spatial directions and the second term describes resistance to volume changes. By formulating the backward Euler time integration scheme as an optimization problem, we show that the first term is invariant to rotations. This allows us to use an operator splitting approach and to solve both terms individually with different numerical methods. The stretching part is solved accurately with an optimization integrator, which can be done very efficiently because the system matrix is constant over time such that its Cholesky factorization can be precomputed. The volume term is solved approximately by using the compliant constraints method and Gauss-Seidel iterations. Further, we introduce the analytic polar decomposition which allows us to speed up the extraction of the rotational part of the deformation gradient and to recover inverted elements. Finally, this results in an extremely fast and robust simulation method with high visual quality that outperforms standard corotated FEMs by more than two orders of magnitude and even the fast but inaccurate PBD and shape matching methods by more than one order of magnitude without having their typical drawbacks. This enables a very efficient simulation of complex scenes containing more than a million elements.

关键词： CCS Concepts •computing methodologies → physical simulation

来源：评论

学校读者我要写书评

暂无评论

Coupled Fluid Density and Motion from Single Views

引用

COMPUTER GRAPHICS FORUM 2018年第8期37卷 47-58页

作者： Eckert, M-L. Heidrich, W. Thuerey, N. Tech Univ Munich Munich Germany King Abdullah Univ Sci & Technol Thuwal Saudi Arabia

We present a novel method to reconstruct a fluid's 3D density and motion based on just a single sequence of images. This is rendered possible by using powerful physical priors for this strongly under-determined problem. More specifically, we propose a novel strategy to infer density updates strongly coupled to previous and current estimates of the flow motion. Additionally, we employ an accurate discretization and depth-based regularizers to compute stable solutions. Using only one view for the reconstruction reduces the complexity of the capturing setup drastically and could even allow for online video databases or smart-phone videos as inputs. The reconstructed 3D velocity can then be flexibly utilized, e.g., for re-simulation, domain modification or guiding purposes. We will demonstrate the capacity of our method with a series of synthetic test cases and the reconstruction of real smoke plumes captured with a Raspberry Pi camera.

关键词： CCS Concepts •computing methodologies → physical simulation Reconstruction •Mathematics of computing → Convex optimization

来源：评论

学校读者我要写书评

暂无评论

MPM simulation of interacting fluids and solids

引用

COMPUTER GRAPHICS FORUM 2018年第8期37卷 183-193页

作者： Yan, X. Li, C-F. Chen, X-S. Hu, S-M. Tsinghua Univ Dept Comp Sci & Technol Beijing Peoples R China Swansea Univ Coll Engn Swansea W Glam Wales

The material point method (MPM) has attracted increasing attention from the graphics community, as it combines the strengths of both particle- and grid-based solvers. Like the smoothed particle hydrodynamics (SPH) scheme, MPM uses particles to discretize the simulation domain and represent the fundamental unknowns. This makes it insensitive to geometric and topological changes, and readily parallelizable on a GPU. Like grid-based solvers, MPM uses a background mesh for calculating spatial derivatives, providing more accurate and more stable results than a purely particle-based scheme. MPM has been very successful in simulating both fluid flow and solid deformation, but less so in dealing with multiple fluids and solids, where the dynamic fluid-solid interaction poses a major challenge. To address this shortcoming of MPM, we propose a new set of mathematical and computational schemes which enable efficient and robust fluid-solid interaction within the MPM framework. These versatile schemes support simulation of both multiphase flow and fully-coupled solid-fluid systems. A series of examples is presented to demonstrate their capabilities and performance in the presence of various interacting fluids and solids, including multiphase flow, fluid-solid interaction, and dissolution.

关键词： CCS Concepts •computing methodologies → physical simulation

来源：评论

学校读者我要写书评

暂无评论

Parallel Multigrid for Nonlinear Cloth simulation

引用

COMPUTER GRAPHICS FORUM 2018年第7期37卷 131-141页

作者： Wang, Zhendong Wu, Longhua Fratarcangeli, Marco Tang, Min Wang, Huamin Zhejiang Univ Hangzhou Zhejiang Peoples R China Ohio State Univ Columbus OH 43210 USA Chalmers Univ Technol Gothenburg Sweden

Accurate high-resolution simulation of cloth is a highly desired computational tool in graphics applications. As single-resolution simulation starts to reach the limit of computational power, we believe the future of cloth simulation is in multi-resolution simulation. In this paper, we explore nonlinearity, adaptive smoothing, and parallelization under a full multigrid (FMG) framework. The foundation of this research is a novel nonlinear FMG method for unstructured meshes. To introduce nonlinearity into FMG, we propose to formulate the smoothing process at each resolution level as the computation of a search direction for the original high-resolution nonlinear optimization problem. We prove that our nonlinear FMG is guaranteed to converge under various conditions and we investigate the improvements to its performance. We present an adaptive smoother which is used to reduce the computational cost in the regions with low residuals already. Compared to normal iterative solvers, our nonlinear FMG method provides faster convergence and better performance for both Newton's method and Projective Dynamics. Our experiment shows our method is efficient, accurate, stable against large time steps, and friendly with GPU parallelization. The performance of the method has a good scalability to the mesh resolution, and the method has good potential to be combined with multi-resolution collision handling for real-time simulation in the future.

关键词： CCS Concepts •computing methodologies → physical simulation

来源：评论

学校读者我要写书评

暂无评论

A Temporally Adaptive Material Point Method with Regional Time Stepping

引用

COMPUTER GRAPHICS FORUM 2018年第8期37卷 195-204页

作者： Fang, Yu Hu, Yuanming Hu, Shi-Min Jiang, Chenfanfu Tsinghua Univ Dept Comp Sci Beijing Peoples R China MIT CSAIL Cambridge MA 02139 USA Univ Penn SIG Ctr Comp Graph Philadelphia PA 19104 USA

Spatially and temporally adaptive algorithms can substantially improve the computational efficiency of many numerical schemes in computational mechanics and physics-based animation. Recently, a crucial need for temporal adaptivity in the Material Point Method (MPM) is emerging due to the potentially substantial variation of material stiffness and velocities in multi-material scenes. In this work, we propose a novel temporally adaptive symplectic Euler scheme for MPM with regional time stepping (RTS), where different time steps are used in different regions. We design a time stepping scheduler operating at the granularity of small blocks to maintain a natural consistency with the hybrid particle/grid nature of MPM. Our method utilizes the Sparse Paged Grid (SPGrid) data structure and simultaneously offers high efficiency and notable ease of implementation with a practical multi-threaded particle-grid transfer strategy. We demonstrate the efficacy of our asynchronous MPM method on various examples including elastic objects, granular media, and fluids.

关键词： CCS Concepts •computing methodologies → physical simulation

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：