PG2019 Short Papers

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https://diglib.eg.org/handle/10.2312/2632814

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Browsing PG2019 Short Papers by Subject "Physical simulation"

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    External Forces Guided Fluid Surface and Volume Reconstruction from Monocular Video
    (The Eurographics Association, 2019) Nie, Xiaoying; Hu, Yong; Su, Zhiyuan; Shen, Xukun; Lee, Jehee and Theobalt, Christian and Wetzstein, Gordon
    We propose a novel method to reconstruct fluid's volume movement and surface details from just a monocular video for the first time. Although many monocular video-based reconstruction methods have been developed, the reconstructed results are merely one layer of geometry surface and lack physically correct volume particles' attribute and movement. To reconstruct 3D fluid volume, we define two kinds of particles, the target particles and the fluid particles. The target particles are extracted from the height field of water surface which is recovered by Shape from Shading (SFS) method. The fluid particles represent the discrete form of the 3D fluid volume and conform to the flow hydrodynamic properties. The target particles are used to guide the physical simulation of fluid particles based on the Smoothed Particle Hydrodynamics (SPH) model. To formulate this guidance, a new external force scheme is designed based on distance and relative motion between target particles and fluid particles. Additionally, in order to integrate and maintain geometric and physical features simultaneously, we adopt a two-scale decomposition strategy for the height field, and only apply the low frequency coarse-scale component to estimate the volumetric motion of liquid, while serve high frequency fine-scale component as noise to preserve fluid surface details in the stage of rendering. Our experimental results compare favorably to the state-of-the-art in terms of global fluid volume motion features and fluid surface details and demonstrate our approach can achieve desirable and pleasing effects.
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    Towards Biomechanically and Visually Plausible Volumetric Cutting Simulation of Deformable Bodies
    (The Eurographics Association, 2019) Qian, Yinling; Huang, Wenbin; Si, Weixin; Liao, Xiangyun; Wang, Qiong; Heng, Pheng-Ann; Lee, Jehee and Theobalt, Christian and Wetzstein, Gordon
    Due to the simplicity and high efficiency, composited finite element method(CFEM) based virtual cutting attracted much attention in the field of virtual surgery in recent years. Even great progress has been made in volumetric cutting of deformable bodies, there are still several open problems restricting its applications in practical surgical simulator. First among them is cutting fracture modelling. Recent methods would produce cutting surface immediately after an intersection between the cutting plane and the object. But in real cutting, biological tissue would first deform under the external force induced by scalpel and then fracture occurs when the stress exceeds a threshold. Secondly, it's computation-intensive to reconstruct cutting surface highly consistent with the scalpel trajectory, since reconstructed cutting surface in CFEM-based virtual cutting simulation is grid-dependent and the accuracy of cutting surface is proportional to the grid resolution. This paper propose a virtual cutting method based on CFEM which can effectively simulate cutting fracture in a biomechanically and visually plausible way and generate cutting surface which is consistent with the scalpel trajectory with a low resolution finite element grid. We model this realistic cutting as a deformation-fracture repeating process. In deformation stage, the object will deform along with the scalpel motion, while in the fracture stage cutting happens and a cutting surface will be generated from the scalpel trajectory. A delayed fracturing criteria is proposed to determine when and how the cutting fracture occurs and an influence domain adaptation method is employed to generate accurate cutting surface in both procedures of deformation and fracture. Experiments show that our method can realistically simulate volumetric cutting of deformable bodies and efficiently generate accurate cutting surface thus facilitating interactive applications.