Mengyuan Ge , Junfeng Yao , Baorong Yang , Ningna Wang , Zhonggui Chen , Xiaohu Guo
{"title":"RBF-MAT: Computing medial axis transform from point clouds by optimizing radial basis functions","authors":"Mengyuan Ge , Junfeng Yao , Baorong Yang , Ningna Wang , Zhonggui Chen , Xiaohu Guo","doi":"10.1016/j.cagd.2025.102421","DOIUrl":"10.1016/j.cagd.2025.102421","url":null,"abstract":"<div><div>In this paper, we present a simple yet effective method RBF-MAT, for computing medial axis transform (MAT) from point cloud using radial basis functions (RBFs), where the surface is represented as the zero-level set of an interpolating function composed of a linear combination of RBFs. Firstly, we propose a new strategy for selecting the initial medial spheres based on the Voronoi vertices computed from the input points while preserving necessary geometric characteristics. Then the centers and radii of the generated medial spheres are iteratively optimized by minimizing the RBF-based surface reconstruction error. Additionally, the connectivity of the refined medial spheres is constructed as the dual of the restricted power diagram for these spheres. Experimental results across diverse 3D shapes demonstrate our method's efficacy in capturing global structural attributes and local geometric intricacies, with our connectivity approach surpassing existing methods. Besides, the experimental results show that the MATs computed with our method better approximate the point cloud surface than state-of-the-art methods.</div></div>","PeriodicalId":55226,"journal":{"name":"Computer Aided Geometric Design","volume":"118 ","pages":"Article 102421"},"PeriodicalIF":1.3,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143563232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sonia Pérez-Díaz , Li-Yong Shen , Xin-Yu Wang , R. Magdalena-Benedicto
{"title":"Infinity branches and asymptotic analysis of algebraic space curves: New techniques and applications","authors":"Sonia Pérez-Díaz , Li-Yong Shen , Xin-Yu Wang , R. Magdalena-Benedicto","doi":"10.1016/j.cagd.2025.102422","DOIUrl":"10.1016/j.cagd.2025.102422","url":null,"abstract":"<div><div>Let <span><math><mi>C</mi></math></span> represent an irreducible algebraic space curve defined by the real polynomials <span><math><msub><mrow><mi>f</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>(</mo><msub><mrow><mi>x</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>x</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>,</mo><msub><mrow><mi>x</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>)</mo></math></span> for <span><math><mi>i</mi><mo>=</mo><mn>1</mn><mo>,</mo><mn>2</mn></math></span>. It is a recognized fact that a birational relationship invariably exists between the points on <span><math><mi>C</mi></math></span> and those on an associated irreducible plane curve, denoted as <span><math><msup><mrow><mi>C</mi></mrow><mrow><mi>p</mi></mrow></msup></math></span>. In this work, we leverage this established relationship to delineate the asymptotic behavior of <span><math><mi>C</mi></math></span> by examining the asymptotes of <span><math><msub><mrow><mi>C</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span>. Building on this foundation, we introduce a novel and practical algorithm designed to efficiently compute the asymptotes of <span><math><mi>C</mi></math></span>, given that the asymptotes of <span><math><msub><mrow><mi>C</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span> have been ascertained.</div></div>","PeriodicalId":55226,"journal":{"name":"Computer Aided Geometric Design","volume":"117 ","pages":"Article 102422"},"PeriodicalIF":1.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143547933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Approximation properties over self-similar meshes of curved finite elements and applications to subdivision based isogeometric analysis","authors":"Thomas Takacs","doi":"10.1016/j.cagd.2025.102413","DOIUrl":"10.1016/j.cagd.2025.102413","url":null,"abstract":"<div><div>In this study we consider domains that are composed of an infinite sequence of self-similar rings and corresponding finite element spaces over those domains. The rings are parameterized using piecewise polynomial or tensor-product B-spline mappings of degree <em>q</em> over quadrilateral meshes. We then consider finite element discretizations which, over each ring, are mapped, piecewise polynomial functions of degree <em>p</em>. Such domains that are composed of self-similar rings may be created through a subdivision scheme or from a scaled boundary parameterization.</div><div>We study approximation properties over such recursively parameterized domains. The main finding is that, for generic isoparametric discretizations (i.e., where <span><math><mi>p</mi><mo>=</mo><mi>q</mi></math></span>), the approximation properties always depend only on the degree of polynomials that can be reproduced exactly in the physical domain and not on the degree <em>p</em> of the mapped elements. Especially, in general, <span><math><msup><mrow><mi>L</mi></mrow><mrow><mo>∞</mo></mrow></msup></math></span>-errors converge at most with the rate <span><math><msup><mrow><mi>h</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span>, where <em>h</em> is the mesh size, independent of the degree <span><math><mi>p</mi><mo>=</mo><mi>q</mi></math></span>. This has implications for subdivision based isogeometric analysis, which we will discuss in this paper.</div></div>","PeriodicalId":55226,"journal":{"name":"Computer Aided Geometric Design","volume":"116 ","pages":"Article 102413"},"PeriodicalIF":1.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143402940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
{"title":"A C1 simplex-spline basis for the Alfeld split in Rs","authors":"Tom Lyche , Jean-Louis Merrien , Hendrik Speleers","doi":"10.1016/j.cagd.2025.102412","DOIUrl":"10.1016/j.cagd.2025.102412","url":null,"abstract":"<div><div>The Alfeld split is obtained by subdividing a simplex in <span><math><msup><mrow><mi>R</mi></mrow><mrow><mi>s</mi></mrow></msup></math></span> into <span><math><mi>s</mi><mo>+</mo><mn>1</mn></math></span> subsimplices with the barycenter as one of their vertices. On this split, we consider the space of <span><math><msup><mrow><mi>C</mi></mrow><mrow><mn>1</mn></mrow></msup></math></span> splines of degree <em>d</em> (<span><math><mi>d</mi><mo>≥</mo><mi>s</mi><mo>+</mo><mn>1</mn></math></span>), for which we construct a basis of simplex-splines with knots at the barycenter and the vertices of the simplex. The basis consists of two types of simplex-splines: firstly Bernstein polynomials with domain points on the facets of the simplex and secondly certain simplex-splines with at least one knot at the barycenter. Partition of unity, Marsden-like identities, and domain points are shown. We also provide <span><math><msup><mrow><mi>C</mi></mrow><mrow><mn>1</mn></mrow></msup></math></span> smoothness conditions across a facet between two simplices.</div></div>","PeriodicalId":55226,"journal":{"name":"Computer Aided Geometric Design","volume":"117 ","pages":"Article 102412"},"PeriodicalIF":1.3,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143487359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
{"title":"A novel heterogeneous deformable surface model based on elasticity","authors":"Ciyang Zhou, Xingce Wang, Zhongke Wu","doi":"10.1016/j.cagd.2024.102402","DOIUrl":"10.1016/j.cagd.2024.102402","url":null,"abstract":"<div><div>The thin membranes and shells in nature are heterogeneous. They are widely used in surgical simulation, biological techniques, and computer animation. The corresponding surface deformable models can implement dynamic simulations of thin membranes and shells in nature, while most surface deformable models are isotropic and cannot represent thin membranes and shells in nature accurately. Therefore, we propose a novel physically-based heterogeneous deformable surface model. By utilizing the same B-spline basis functions or the parameter space of surfaces' geometric representations, we implement material modeling and propose the representations of surfaces with material variations with composite or continuous material functions. Then, we propose a novel physically-based elastic deformable surface model that constructs infinitesimal elements in the parameter space and employs elasticity to analyze their deformation. The corresponding elastic potential energy function is only related to surfaces' continuous representations, and our model avoids the computation error caused by meshes' quality and large rotation of points' frames. We employ isogeometric analysis to solve the dynamic equations derived from our surface model. To demonstrate the validity and reality of our model, several comparison experiments are designed. The corresponding results are in line with expectations and consistent with physical laws.</div></div>","PeriodicalId":55226,"journal":{"name":"Computer Aided Geometric Design","volume":"115 ","pages":"Article 102402"},"PeriodicalIF":1.3,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Optimal one-sided approximants of circular arc","authors":"Ada Šadl Praprotnik , Aleš Vavpetič , Emil Žagar","doi":"10.1016/j.cagd.2024.102401","DOIUrl":"10.1016/j.cagd.2024.102401","url":null,"abstract":"<div><div>The optimal one-sided parametric polynomial approximants of a circular arc are considered. More precisely, the approximant must be entirely in or out of the underlying circle of an arc. The natural restriction to an arc's approximants interpolating boundary points is assumed. However, the study of approximants, which additionally interpolate corresponding tangent directions and curvatures at the boundary of an arc, is also considered. Several low-degree polynomial approximants are studied in detail. When several solutions fulfilling the interpolation conditions exist, the optimal one is characterized, and a numerical algorithm for its construction is suggested. Theoretical results are demonstrated with several numerical examples and a comparison with general (i.e. non-one-sided) approximants are provided.</div></div>","PeriodicalId":55226,"journal":{"name":"Computer Aided Geometric Design","volume":"115 ","pages":"Article 102401"},"PeriodicalIF":1.3,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Weiming Wang , Shan Li , Li Yang , Jiepeng Liu , Yi Xia , Ligang Liu
{"title":"Build orientation optimization considering thermal distortion in additive manufacturing","authors":"Weiming Wang , Shan Li , Li Yang , Jiepeng Liu , Yi Xia , Ligang Liu","doi":"10.1016/j.cagd.2024.102393","DOIUrl":"10.1016/j.cagd.2024.102393","url":null,"abstract":"<div><div>Additive manufacturing (AM) technology enables the fabrication of three-dimensional objects with complex shapes and has been extensively applied in various industries. AM is a layer-wise fabrication process where a variety of factors affect manufacturing performance and product quality. One of the most important factor is the thermal distortion, which is caused by the high temperature gradients in the fabrication process. The thermal distortion is also influenced by the support structure of the printing object, and this distortion varies depending on the chosen build orientation. Additionally, for the overhang regions, extra supports are required for printing and will be removed in the post-processing. For the 3D printing process, the thermal distortion and support requirements are interconnected and linked to build orientation. To investigate suitable build orientation, the thermal distortion and support are quantified, and a multi-objective build orientation optimization method is proposed to obtain representative orientations. Based on the proposed method, 9 typical 3D shapes are evaluated. In addition, the single-objective build orientation optimization problem is studied and compared, and the influence of slicing layers per stage on the simulation accuracy and efficiency is discussed. The effectiveness and applicability of the method are verified, and representative directions can be obtained for different fabrication purposes.</div></div>","PeriodicalId":55226,"journal":{"name":"Computer Aided Geometric Design","volume":"114 ","pages":"Article 102393"},"PeriodicalIF":1.3,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Algorithms and data structures for Cs-smooth RMB-splines of degree 2s + 1","authors":"Maodong Pan , Ruijie Zou , Bert Jüttler","doi":"10.1016/j.cagd.2024.102389","DOIUrl":"10.1016/j.cagd.2024.102389","url":null,"abstract":"<div><div>The simple mesh refinement algorithm of <span><span>Groiss et al. (2023)</span></span> generates T-meshes admitting Reachable Minimally supported (RM) B-splines that possess the property of local linear independence and form a non-negative partition of unity. The construction was first presented for the bilinear case and has later been extended to <span><math><msup><mrow><mi>C</mi></mrow><mrow><mi>s</mi></mrow></msup></math></span>-smooth splines of degree <span><math><mi>p</mi><mo>=</mo><mn>2</mn><mi>s</mi><mo>+</mo><mn>1</mn></math></span>. The present paper is devoted to algorithms and data structures for RMB-splines. We prove that the memory consumption of the data structures for representing a T-mesh and the associated RMB-splines is linear with respect to the mesh size, and we describe the details of the underlying refinement algorithm. Moreover, we introduce a novel evaluation algorithm for RMB-spline surfaces, which is based solely on repeated convex combinations of the control points, thereby generalizing de Boor's algorithm for tensor-product splines. Numerical experiments are included to demonstrate the advantageous behavior of the proposed data structures and algorithms with respect to their efficiency. We observe that the total computational time (which includes also error estimation and spline coefficient computation) scales roughly linearly with the number of degrees of freedom for the meshes considered.</div></div>","PeriodicalId":55226,"journal":{"name":"Computer Aided Geometric Design","volume":"114 ","pages":"Article 102389"},"PeriodicalIF":1.3,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xiaoge He , Yuanpeng Liu , Jun Zhou , Yuqi Zhang , Jun Wang
{"title":"Efficient object recognition under cluttered scenes via descriptor-based matching and single point voting","authors":"Xiaoge He , Yuanpeng Liu , Jun Zhou , Yuqi Zhang , Jun Wang","doi":"10.1016/j.cagd.2024.102394","DOIUrl":"10.1016/j.cagd.2024.102394","url":null,"abstract":"<div><div>This paper addresses the problem of recognizing multiple objects and multiple instances from point clouds. Whereas existing methods utilize descriptors on 3D fields or pointwise voting to achieve this task, our framework takes advantage of both descriptor-based and voting-based schemes to realize more robust and efficient prediction. Specifically, we propose a novel and robust descriptor called an orientation-enhanced fast point feature histogram (OE-FPFH) to describe points in both the object model and scene, and further to build the correspondence set. The OE-FPFH integrates an orientation vector through mining the geometric tensor of the local structure of a surface point, which is more representative than the original FPFH descriptor. To improve voting efficiency, we devise a novel single-point voting mechanism (SPVM), which constructs a unique local reference frame (LRF) on a single point using the orientation vector. The SPVM takes as input the corresponding point set and can generate a pose candidate for each correspondence. The process is realized by matching LRFs from two corresponding points. All pose candidates are subsequently divided into clusters and aggregated using the <em>K</em>-means clustering algorithm to deduce the poses for different objects or instances in the scene. Experiments on three challenging datasets demonstrate that our method is effective, efficient, and robust to occlusions and multiple instances.</div></div>","PeriodicalId":55226,"journal":{"name":"Computer Aided Geometric Design","volume":"114 ","pages":"Article 102394"},"PeriodicalIF":1.3,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142442502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Curvature continuous corner cutting","authors":"Kai Hormann , Claudio Mancinelli","doi":"10.1016/j.cagd.2024.102392","DOIUrl":"10.1016/j.cagd.2024.102392","url":null,"abstract":"<div><div>Subdivision schemes are used to generate smooth curves by iteratively refining an initial control polygon. The simplest such schemes are corner cutting schemes, which specify two distinct points on each edge of the current polygon and connect them to get the refined polygon, thus cutting off the corners of the current polygon. While <span><span>de Boor (1987)</span></span> shows that this process always converges to a Lipschitz continuous limit curve, no matter how the points on each edge are chosen, <span><span>Gregory and Qu (1996)</span></span> discover that the limit curve is continuously differentiable under certain constraints. We extend these results and show that the limit curve can even be curvature continuous for specific sequences of cut ratios.</div></div>","PeriodicalId":55226,"journal":{"name":"Computer Aided Geometric Design","volume":"114 ","pages":"Article 102392"},"PeriodicalIF":1.3,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142437820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}