The process of surface reconstruction has received considerable interest from researchers in recent years. Surface reconstruction plays a major role in many applications, such as visualization, geometric modeling and ...
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The process of surface reconstruction has received considerable interest from researchers in recent years. Surface reconstruction plays a major role in many applications, such as visualization, geometric modeling and multiresolution analysis. In this paper, we present an approach that approximates a surface from a set of oriented points. Our algorithm combines the implicit surface and frequency-based frameworks to convert the indicator function of the surface into an implicit function from which we can extract the required surface. In contrast to traditional frequency-based approaches, our approach avoids voxelization of the input points and calculates the Fourier coefficients directly from the surface, which reduces the amount of memory required to settle the voxel grid and eliminates the mathematical errors correspond-ing to this voxelization. In addition, we exploit the recent advances of GPUs embedded in graphics cards to accelerate the calculation of the Fourier coefficients. Finally, some examples are given to demonstrate the validity of the proposed technique. (c) 2020 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://***/licenses/by-nc-nd/4.0/).
The metaverse is a visual world that blends the physical world and digital *** present,the development of the metaverse is still in the early stage,and there lacks a framework for the visual construction and explorati...
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The metaverse is a visual world that blends the physical world and digital *** present,the development of the metaverse is still in the early stage,and there lacks a framework for the visual construction and exploration of the *** this paper,we propose a framework that summarizes how graphics,interaction,and visualization techniques support the visual construction of the metaverse and user-centric *** introduce three kinds of visual elements that compose the metaverse and the two graphical construction methods in a *** propose a taxonomy of interaction technologies based on interaction tasks,user actions,feedback and various sensory channels,and a taxonomy of visualization techniques that assist user *** potential applications and future opportunities are discussed in the context of visual construction and exploration of the *** hope this paper can provide a stepping stone for further research in the area of graphics,interaction and visualization in the metaverse.
Clipping, as a fundamental process in computer graphics, displays only the part of a scene which is needed to be displayed and rejects all others. In two dimensions, the clipping process can be applied to a variety of...
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Clipping, as a fundamental process in computer graphics, displays only the part of a scene which is needed to be displayed and rejects all others. In two dimensions, the clipping process can be applied to a variety of geometric primitives such as points, lines, polygons or curves. A line-clipping algorithm processes each line in a scene through a series of tests and intersection calculations to determine whether the entire line or any part of it is to be saved. It also calculates the intersection position of a line with the window edges so its major goal is to minimize these calculations. This article surveys important techniques and algorithms for line-clipping in 2D but it also includes some of the latest research made by the authors. The survey criteria include evaluation of all line-clipping algorithms against a rectangular window, line clipping versus polygon clipping, and our line clipping against a convex polygon, as well as all line-clipping algorithms against a convex polygon algorithm.
Slender structures, widely found from natural environments (e.g., tendrils) to engineering applications (e.g., flexible electronics), frequently experience geometrically nonlinear deformations and substantial topologi...
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Slender structures, widely found from natural environments (e.g., tendrils) to engineering applications (e.g., flexible electronics), frequently experience geometrically nonlinear deformations and substantial topological changes when exposed to simple boundary conditions or modest external stimuli. On one hand, the nonlinear dynamics of slender structures present considerable challenges for the automated manipulation of these structures by robots. On the other hand, the automated interactions between robots and such structures also open up opportunities to enhance our understanding of the mechanics governing slender structures. This dissertation focuses on the synergy between computational mechanics and robotics for the manipulation and study of slender structures. Specifically, it delves into discrete differential geometry (DDG)-based simulations, an emerging field in computational mechanics, to develop a comprehensive sim2Real manipulation framework for generating task-oriented deformable manipulation strategies. Moreover, we conduct automated experiments to gain valuable insights into the behavior of slender structures. Our contributions can be categorized into three main areas: First, we develop a penalty-energy-based method and combine it with Kirchoff rod’s theory to simulate rod assemblies with frictional contact responses. Our simulation method is validated, demonstrating its robustness, accuracy, and efficiency across diverse scenarios. These scenarios include modeling flagella bundling, a significant biological phenomenon for bacterial navigation, as well as tying knots. These numerical validations underscore the potential of our approach as a significant step toward the ultimate goal of a computational framework for sim2real manipulation tasks. We then combine our numerical framework with desktop experiments to investigate the mechanics of various types of knots. Second, we combine DDG-based simulations, scaling analysis, and machine learning to develop a
Recent trends in computer science have emphasized the use of numerical optimization methodologies in physically-based simulations. By treating time-stepping problems as optimization targets and employing optimization ...
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Recent trends in computer science have emphasized the use of numerical optimization methodologies in physically-based simulations. By treating time-stepping problems as optimization targets and employing optimization techniques, both the accuracy and efficiency of solvers have been significantly improved. This thesis begins with an exploration of nonlinear optimization theory, then proceeds to present novel algorithms designed to simulate non-equilibrated viscoelastic and elastoplastic solids implicitly, even under large time steps. Collaborative efforts within the computer graphics community have enabled the realistic digital reproduction of various daily life materials, such as snow, sand, water, and jelly. These research breakthroughs have had profound implications across diverse fields, such as gaming, film production, fashion design, robotics, and mechanical engineering analysis. Among the myriad of applications, the concept of contact remains a vital factor influencing simulation results, which motivated us to refocus our research on this area. Free-slip contact, frictional contact, and adhesive contact each exhibit their unique characteristics when integrated with different numerical methods. For meshless methods, like the Material Point Method (MPM), the presence of a background grid confers advantages in automatic collision detection, although the contacting surface is only implicitly defined. Conversely, mesh-based methods, such as the Finite Element Method (FEM), require considerable effort to query exact primitive contacting pairs. Due to the strict definition of the mesh, intersections must be entirely eliminated to avoid introducing significant artifacts in later stages of the process. Notably, in addition to providing visual enjoyment with complex contact scenarios, our framework boasts many other functionalities, including the ability to create new shapes that mimic human craftsmanship and the capacity to align closely with real-world experimental re
The article investigates an urgent problem of computer graphics, the problem of rendering. It is shown that, due to the increasing complexity of applied problems, the process of rendering is becoming increasingly cost...
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The article investigates an urgent problem of computer graphics, the problem of rendering. It is shown that, due to the increasing complexity of applied problems, the process of rendering is becoming increasingly costly and difficult to control. These factors demand the constant development and improvement of the graphics pipeline technology. The article proposes an approach in which an attempt is made to build a general methodology for solving the problem of rendering based on the use of mathematical formalisms. It is shown that this creates good prerequisites for further automation of the functionality of the graphics pipeline.
3D printing and other modern manufacturing technologies enabled accessible customized fabrication of small-batch and unique objects, with unparalleled flexibility in shape design. However, creating structures that are...
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3D printing and other modern manufacturing technologies enabled accessible customized fabrication of small-batch and unique objects, with unparalleled flexibility in shape design. However, creating structures that are able to meet the design requirements is not an easy task, and doing it manually can be a very slow and tedious process. In this context, structural optimization techniques can be very useful and help automate the design and analysis process. This thesis describes techniques that expand the usage of structural optimization for digital fabrication by formulating optimization to be used with more realistic simulation models. We develop an efficient method (differentiable simulation) to compute gradients of optimization objectives depending on solutions of the physical deformation equations, which can be used to optimize the shape, material, and physical properties of our domain. We provide ways of expanding the use of two-scale topology optimization by presenting microstructures that have a smooth map from material to geometry and which can be used on curved shapes defined by irregular lattices with close to rhombic cells. Finally, we introduce two low-parametric microstructures that together are able to cover almost the whole possible range of elastic properties for isotropic metamaterials. Our results in simulation and physical experiments, both for static and time-dependent scenarios, show the advantages of our techniques and how they can be applied in practice.
Digital video is more prevalent nowadays because of more usage of video data among users. The short and catchy videos among social media attract the attention of people. On the same time, the lengthy videos are found ...
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This article reviews the issues and challenges of digital video composition to identify the problem in educational video production. The review of related literature discussed four components that lead to the issues a...
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Human action recognition is the process of automatically recognizing human activities in digital video sequences. It is an important research topic in computer vision, particularly in the field of video surveillance. ...
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