Computer-Aided Design最新文献

eCAD-Net: Editable Parametric CAD Models Reconstruction from Dumb B-Rep Models Using Deep Neural Networks eCAD-Net：利用深度神经网络从呆板的 B-Rep 模型重建可编辑的参数化 CAD 模型

IF 3 3区计算机科学

Computer-Aided Design Pub Date : 2024-09-24 DOI: 10.1016/j.cad.2024.103806

引用次数: 0

Multi-part kinematic constraint prediction for automatic generation of CAD model assemblies using graph convolutional networks 利用图卷积网络自动生成 CAD 模型装配的多部分运动学约束预测

IF 3 3区计算机科学

Computer-Aided Design Pub Date : 2024-09-21 DOI: 10.1016/j.cad.2024.103805

{"title":"Multi-part kinematic constraint prediction for automatic generation of CAD model assemblies using graph convolutional networks","authors":"","doi":"10.1016/j.cad.2024.103805","DOIUrl":"10.1016/j.cad.2024.103805","url":null,"abstract":"<div><div>This paper presents a machine learning-based approach to predict kinematic constraints between CAD models that have potentially never been assembled together before. During the learning phase, the algorithm is trained to predict the next-possible-constraints between a set of parts candidate to the assembly. Assemblies are represented in a new graph-based formalism that is capable of capturing features associated with parts, interfaces between parts and constraints between them. Using such a multi-level feature extraction strategy coupled to a state-by-state graph decomposition, the approach does not need to be trained on a large database. This formalism is used to model both the network input and output where the next-possible-constraints appear after evaluation. The core of the approach relies on a series of networks based on a link-prediction encoder–decoder architecture, integrating the capabilities of several convolutional networks trained in an end-to-end manner. A decision-making algorithm is added to post-process the output and drive the prediction process in finding one among the set of next-possible-constraints. This process is repeated until no more constraints can be added. The experimental results show that the proposed approach outperforms state-of-the-art methods on such assembly tasks. Although the state-by-state assembly algorithm is iterative, it still takes into account the whole set of parts as well as the whole set of constraints already predicted, and this makes it possible to handle constraint cycles, which is generally not possible when not considering multiple parts as input.</div></div>","PeriodicalId":50632,"journal":{"name":"Computer-Aided Design","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142318590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Efficient evaluation of Bernstein-Bézier coefficients of B-spline basis functions over one knot span 在一个节点跨度上高效评估 B-样条曲线基函数的伯恩斯坦-贝塞尔系数

IF 3 3区计算机科学

Computer-Aided Design Pub Date : 2024-09-19 DOI: 10.1016/j.cad.2024.103804

引用次数: 0

Computational design of asymptotic geodesic hybrid gridshells via propagation algorithms 通过传播算法计算设计渐近大地混合网格壳

IF 3 3区计算机科学

Computer-Aided Design Pub Date : 2024-09-12 DOI: 10.1016/j.cad.2024.103800

引用次数: 0

Point containment algorithms for constructive solid geometry with unbounded primitives 无界基元构造实体几何的点包含算法

IF 3 3区计算机科学

Computer-Aided Design Pub Date : 2024-09-11 DOI: 10.1016/j.cad.2024.103803

{"title":"Point containment algorithms for constructive solid geometry with unbounded primitives","authors":"","doi":"10.1016/j.cad.2024.103803","DOIUrl":"10.1016/j.cad.2024.103803","url":null,"abstract":"<div><p>We present several algorithms for evaluating point containment in constructive solid geometry (CSG) trees with unbounded primitives. Three algorithms are presented based on postfix, prefix, and infix notations of the CSG binary expression tree. We show that prefix and infix notations enable short-circuiting logic, which reduces the number of primitives that must be checked during point containment. To evaluate the performance of the algorithms, each algorithm was implemented in the OpenMC Monte Carlo particle transport code, which relies on CSG to represent solid bodies through which subatomic particles travel. Two sets of tests were carried out. First, the execution time to generate a rasterized image of a 2D slice of three CSG models of varying complexity was measured. Use of both prefix and infix notations offered significant speedup over the postfix notation that has traditionally been used in particle transport codes, with infix resulting in a 6<span><math><mo>×</mo></math></span> reduction in execution time relative to postfix for a model of a tokamak fusion device. We then measured the execution time of neutron transport simulations of the same three models using each of the algorithms. The results and performance improvements reveal the same trends as for the rasterization test, with a 5.52<span><math><mo>×</mo></math></span> overall speedup using the infix notation relative to the original postfix notation in OpenMC for the tokamak model.</p></div>","PeriodicalId":50632,"journal":{"name":"Computer-Aided Design","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0010448524001301/pdfft?md5=8fddc42a59401cae480fb7d7905061a3&pid=1-s2.0-S0010448524001301-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142230589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Tessellation and interactive visualization of four-dimensional spacetime geometries 四维时空几何图形的细分和交互式可视化

IF 3 3区计算机科学

Computer-Aided Design Pub Date : 2024-08-24 DOI: 10.1016/j.cad.2024.103792

{"title":"Tessellation and interactive visualization of four-dimensional spacetime geometries","authors":"","doi":"10.1016/j.cad.2024.103792","DOIUrl":"10.1016/j.cad.2024.103792","url":null,"abstract":"<div><p>This paper addresses two problems needed to support four-dimensional (<span><math><mrow><mn>3</mn><mi>d</mi><mo>+</mo><mi>t</mi></mrow></math></span>) spacetime numerical simulations. The first contribution is a general algorithm for producing conforming spacetime meshes of moving geometries. Here, the surface points of the geometry are embedded in a four-dimensional space as the geometry moves in time. The geometry is first tessellated at prescribed time steps and then these tessellations are connected in the parameter space of each geometry entity to form tetrahedra. In contrast to previous work, this approach allows the resolution of the geometry to be controlled at each time step. The only restriction on the algorithm is the requirement that no topological changes to the geometry are made (i.e. the hierarchical relations between all geometry entities are maintained) as the geometry moves in time. The validity of the final mesh topology is verified by ensuring the tetrahedralizations represent a closed 3-manifold. For some analytic problems, the <span><math><mrow><mn>4</mn><mi>d</mi></mrow></math></span> volume of the tetrahedralization is also verified. The second problem addressed in this paper is the design of a system to interactively visualize four-dimensional meshes when the <span><math><mrow><mn>4</mn><mi>d</mi></mrow></math></span> view changes, including tetrahedra (embedded in <span><math><mrow><mn>4</mn><mi>d</mi></mrow></math></span>) and pentatopes. Algorithms that either include or exclude a geometry shader are described, and the efficiency of each approach is then compared. Overall, the results suggest that visualizing tetrahedra (either those bounding the domain, or extracted from a pentatopal mesh) using a geometry shader achieves the highest frame rate, realizing interactive frame rates of at least 15 frames per second for meshes with about 50 million tetrahedra.</p></div>","PeriodicalId":50632,"journal":{"name":"Computer-Aided Design","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0010448524001192/pdfft?md5=e51e1de5cf978ffc80f6145b0ad55e2e&pid=1-s2.0-S0010448524001192-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142117737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Topology-aware blending method for implicit heterogeneous porous model design 用于隐式异质多孔模型设计的拓扑感知混合法

IF 3 3区计算机科学

Computer-Aided Design Pub Date : 2024-08-08 DOI: 10.1016/j.cad.2024.103782

{"title":"Topology-aware blending method for implicit heterogeneous porous model design","authors":"","doi":"10.1016/j.cad.2024.103782","DOIUrl":"10.1016/j.cad.2024.103782","url":null,"abstract":"<div><p>Porous structures are materials consisting of minuscule pores, where the microstructure morphology significantly impacts their macroscopic properties. Integrating different porous structures through a blending method is indispensable to cater to diverse functional regions in heterogeneous models. Previous studies on blending methods for porous structures have mainly focused on controlling the shape of blending regions, yet they have fallen short in effectively addressing topological errors in blended structures. This paper introduces a new blending method that successfully addresses this issue. Initially, a novel initialization method is proposed, which includes distinct strategies for blending regions of varying complexities. Subsequently, we formulate the challenge of eliminating topological errors as an optimization problem based on persistent homology. Through iterative updates of control coefficients, this optimization problem is solved to generate a blended porous structure. Our approach not only avoids topological errors but also governs the shape and positioning of the blending region while remaining unchanged in the structure outside blending region. The experimental outcomes validate the effectiveness of our method in producing high-quality blended porous structures. Furthermore, these results highlight potential applications of our blending method in biomimetics and the design of high-stiffness mechanical heterogeneous models.</p></div>","PeriodicalId":50632,"journal":{"name":"Computer-Aided Design","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141993065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Handlebody Plesiohedra Unchained: Topologically Interlocked Cell-Transitive 3-Honeycombs 解锁的手体 Plesiohedra：拓扑互锁细胞传递 3-蜂巢

IF 3 3区计算机科学

Computer-Aided Design Pub Date : 2024-08-08 DOI: 10.1016/j.cad.2024.103779

{"title":"Handlebody Plesiohedra Unchained: Topologically Interlocked Cell-Transitive 3-Honeycombs","authors":"","doi":"10.1016/j.cad.2024.103779","DOIUrl":"10.1016/j.cad.2024.103779","url":null,"abstract":"<div><p>We present an approach for systematic design of generalized Plesiohedra, a new type of 3D space-filling shapes that can even include unchained handlebodies. We call these handlebody plesiohedra unchained, since they are <strong>topologically interlocked</strong>, i.e., they can be assembled and disassembled without breaking any of the solids apart and they can keep in place with a set of boundary constraints. These space-filling shapes (i.e. congruent prototiles) are obtained from the Voronoi decomposition of symmetric Delone (Delaunay) point sets. To create this new class of shapes, we generalize the design space of classical Plesiohedra by introducing two novel geometric steps: (a) extension of point sites to piecewise linear approximations of higher-dimensional geometries and (b) extension of symmetries to 3D crystallographic symmetries. We show how these specific collections of higher-dimensional geometries can admit the symmetric Delone property. A Voronoi partitioning of 3D space using these specific collections of higher-dimensional shapes as Voronoi sites naturally results in congruent prototiles. This generalizes the idea of classical Plesiohedra by allowing for piecewise linear approximation of curved edges and faces, non-convex boundaries, and even handlebodies with positive genus boundaries to provide truly volumetric material systems in contrast to traditional planar or shell-like systems. To demonstrate existence of these solid shapes, we produced a large set of unchained congruent space-filling handlebodies as proofs of concept. For this, we focused our investigation using isometries of some space-filling polyhedra, such as a cube and a truncated octahedron with circles, and curve complexes as Voronoi sites. These results point to a rich and vast parametric design space of unchained handlebody plesiohedra making them an excellent representations for engineering applications such as topologically interlocked architectured materials.</p></div>","PeriodicalId":50632,"journal":{"name":"Computer-Aided Design","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141964515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Optimum design of uniform and non-uniform infill-coated structures with discrete variables 具有离散变量的均匀和非均匀灌注涂层结构的优化设计

IF 3 3区计算机科学

Computer-Aided Design Pub Date : 2024-08-05 DOI: 10.1016/j.cad.2024.103781

{"title":"Optimum design of uniform and non-uniform infill-coated structures with discrete variables","authors":"","doi":"10.1016/j.cad.2024.103781","DOIUrl":"10.1016/j.cad.2024.103781","url":null,"abstract":"<div><p>This article introduces a novel computer-aided procedure to design optimised coated structures with precise shell thickness control using the Smallest Univalue Segment Assimilating Nucleus operator and a novel augmentation-projection technique. Structures with heterogeneous sections, or coated structures, combine two different materials for the nucleus and the shell, which are generally chosen so that the material in the infill is lighter and the material in the coating is stiffer, which in this work are supposed homogeneous. Solving the interface problem requires material properties interpolation equations that consider three material phases, accurate placement of the coating over the base material, and precise control over the coating's thickness. The formation of the coating is controlled by the <em>Smallest Univalue Segment Assimilating Nucleus</em>, an edge detection operator developed in <em>Digital Image Processing</em>. The coating's thickness is controlled by an innovative methodology consisting of the projection of an augmented contour field, which is shown to create a constant thickness coating around the material domain. The optimisation problem is solved with the <em>Sequential Element Rejection and Admission</em> method. The validity of the procedure has been verified by solving various numerical application examples.</p></div>","PeriodicalId":50632,"journal":{"name":"Computer-Aided Design","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0010448524001088/pdfft?md5=818e970a6501d02a83f834dc682faba0&pid=1-s2.0-S0010448524001088-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141993064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Structural regularity detection and enhancement for surface mesh reconstruction in reverse engineering 用于逆向工程中曲面网格重建的结构规整性检测与增强

IF 3 3区计算机科学

Computer-Aided Design Pub Date : 2024-08-02 DOI: 10.1016/j.cad.2024.103780

引用次数: 0