CAD'22 Proceedings最新文献

{"title":"Research on Profile Geometric Feature Parameters Extraction of Complicated Thin-walled Ring Parts with Irregular Section","authors":"Haonan Pei, Ming Luo, Sizhe Du","doi":"10.14733/cadconfp.2022.372-376","DOIUrl":"https://doi.org/10.14733/cadconfp.2022.372-376","url":null,"abstract":"Introduction: The metallic W-ring is a typically complicated thin-walled ring part with irregular section, due to its multi-pass forming, closed ring structure, complex cross-sectional profile and small size, it is difficult to design CAD model of each forming pass in short cycle and low cost. The inverse modeling solution based on point cloud slicing is an effective way to reconstruct the ring parts. However, the lack of feature representation usually results in inaccurate and inconsistent topological CAD model. Consequently, it is difficult to represent the original design intention and to modify the final model parameters in an effective way [4]. On the other hand, the parametric representation of intermediate part geometric features is also the basis for the automatic process planning knowledge base.","PeriodicalId":316648,"journal":{"name":"CAD'22 Proceedings","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127269638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Automatic Assembly Sequence Planning for Axisymmetric Products","authors":"Brigida Bonino, F. Giannini, M. Monti, Roberto Raffaeli","doi":"10.14733/cadconfp.2022.334-338","DOIUrl":"https://doi.org/10.14733/cadconfp.2022.334-338","url":null,"abstract":"Introduction: In industrial manufacturing the production of mechanical assemblies is demanding in all its stages. Due to the increasing complexity of products, design, management, and end of life phases are becoming very onerous and time consuming tasks [8]. As a consequence, in the last decades, technologies have been studied to facilitate production and automate di erent manufacturing operations to reduce time and costs of production, avoid human errors and increase product quality as well as industrial collaboration. In this regard, Assembly Sequence Planning (ASP) is considered one of most challenging topic in the industrial manufacturing eld, and still deserves to be explored and further developed. ASP aims at algorithmically identifying the order in which components have to be assembled to obtain the nal product. It starts from a CAD assembly model and, by analyzing and extracting part geometric features and relations, returns admissible sequences. Multiple solutions can exist on how mounting components with each other, but the selection of one sequence rather than another has great e ect on assembly feasibility, complexity, and accuracy. Moreover, ASP is known to be a very hard combinatory problem while the assembly parts numbers become important [13]. To reduce the complexity, Subassembly Identi cation (SI) often precedes the sequence planning, in order to apply sequence generation approaches to each subassembly reducing the amount of parts to consider at the same time. However the main weakness observed is that all the data extracted basically relay on geometric information, while the engineering meanings of the assembly/subassembly and its components are not considered. For example, knowing if all the parts are arranged in a speci c manner, e.g along a common axis or connected by screws with a precise orientation, would be bene cial in the selection of the assembly direction. Or else, the awareness of deformable components (e.g. circlips, O-ring, etc.) or fasteners allows to make conclusions on their assembly order even when the geometric analysis of precedences is ambiguous. The work here presented is placed in this context and, speci cally, it deals with axisymmetric clusters, i.e. connected groups of parts symmetrical to an axis, all aggregated along the same direction. These groups of parts deserve to be singularly analyzed because they are elements occurring frequently in mechanics, that most of the time can be treated independently of the larger assembly containing them (e.g. crankshafts, pulleys and rollers). Distinctive features of axisymmetric subassemblies are the mounting techniques (i.e. threading by sliding or tting hollow parts into the axis), the fasteners included (i.e.","PeriodicalId":316648,"journal":{"name":"CAD'22 Proceedings","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123377104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exact Signed Distance Function Representation of Polygons","authors":"Csaba Bálint, Gábor Valasek, Róbert Bán","doi":"10.14733/cadconfp.2022.292-296","DOIUrl":"https://doi.org/10.14733/cadconfp.2022.292-296","url":null,"abstract":"Introduction: Signed distance functions (SDF) are applied from high-quality text rendering [3] to geometric representation for collision detection [5], 3D printing, additive manufacturing [1], or advanced real-time graphics e ects [7]. The SDF is usually stored as a regular grid of samples for high-performance applications, but various spatial subdivision or interpolation schemes have been proposed for storage, such as octrees [2] or hierarchical T-meshes [6]. In complex shapes, applications mainly focus on storing a discrete approximation to the exact SDF in conjunction with various interpolation techniques. We propose a conservative but exact SDF representation for planar polygons. The exact SDF is composed of two classes of regions, separated by parabolic and linear boundaries. We construct conservative polygonal bounds to these regions. Our algorithm performs a series of cuts to determine the bounding polygons that represent the distance function on the region. The exact SDF can be evaluated using these polygons. Such a formulation is closely related to point and segment Voronoi diagrams [4]; however, our goal is to preserve the inside-outside partitioning of the plane as well.","PeriodicalId":316648,"journal":{"name":"CAD'22 Proceedings","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132482310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhancing Size Perception with True-Size Viewing CAD plug-in and Cloud-enabled AR APP","authors":"Junjian Chen, Zhongyuan Liao, Y. Cai","doi":"10.14733/cadconfp.2022.318-323","DOIUrl":"https://doi.org/10.14733/cadconfp.2022.318-323","url":null,"abstract":"Introduction: Compared with sketching or viewing the drawing on paper at the scale of 1:1, it is difficult to have an intuitive understanding of the part size when designing and viewing models in CAD software since the displayed size usually differs from its true size[2]. The reason for this is the inaccurate size perceiving process. Size perception refers to the complex cognitive behavior of interpreting the spatial geometry magnitude of objects[5][10]. A familiar object's perceived size remains identical regardless of the changing distance[8]. This phenomenon is known as size constancy[11], and it helps humans estimate the size of unfamiliar objects. However, the part in the CAD is usually of low familiarity and presented without any familiar object, so the size perception is based on the perceived target distance and the visual angle. When observing a virtual object shown on the monitor, the convergence of two eyeballs focusing on the same object plays the most important role among all cues[3][9]. 3D CAD software uses the 2D image of a virtual camera targeting the model located at a virtual distance to display 3D models. The viewer perceives the displayed size instead of the true size, while the perceived target distance is the distance between the viewer's eyes and the monitor. Even when the virtual model is placed in a virtual environment identical to the real scene, it is also perceived to be smaller than the real object, although the retinal size is the same[12]. The CAD Window will show all the Camera Range, and the ratio of CAD Window Size to the Displayed Size equals the one of Max Camera Range to True Size. Fig. 1 is listed below to illustrate the display method in the 3D CAD more clearly.","PeriodicalId":316648,"journal":{"name":"CAD'22 Proceedings","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115008302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research on the Pattern Extraction of Academy of Classical Learning’s Buildings based on Image Enhancement Technology","authors":"Kan Wu, Mengxi Jia","doi":"10.14733/cadconfp.2022.355-359","DOIUrl":"https://doi.org/10.14733/cadconfp.2022.355-359","url":null,"abstract":"Conclusion This paper proposes a workflow for extracting architectural decorative patterns based on image enhancement technology and computer-aided design tools, including image enhancement and pattern standardization correction and extraction. The extraction results of typical pattern samples show that this workflow can batch enhance architectural decoration image materials, enhance their recognition and extract standard patterns. To a certain extent, this workflow can effectively reduce the equipment and material sampling environment requirements for the on-site acquisition of architectural decorative patterns and improve the availability of original materials. On this basis, geometric auxiliary lines can quickly locate the patterns in the image and reduce the difficulty of detail extraction. The features and innovations of this research are as follows: (1) A systematic, standardized, and efficient workflow based on computer-aided design technology is proposed for the problem of insufficient systematisms and low efficiency in the extraction of architectural decorative patterns. The innovative application of the CLAHE algorithm and adaptive bilateral filtering optimizes the problems of inefficiency and limited expertise produced by using PS to preprocess images. At the same time, it is proposed to use computer-aided design tools to draw geometric auxiliary lines for standardized correction and extraction of patterns, which significantly reduces the time cost and difficulty of pattern extraction. (2) This process simplifies the work of pattern extraction to drawing, cutting, and connecting simple geometric auxiliary lines, which breaks the limitation of professional ability. Even non-design researchers can quickly get started and perform pattern extraction. In addition, this pattern standardization extraction process is universal and applies to the digitization of all complex traditional patterns. present, this workflow still In research, researchers can try to realize automatic pattern extraction through edge recognition, curve fitting, machine learning, and other technologies based on the auxiliary line extraction method in paper.","PeriodicalId":316648,"journal":{"name":"CAD'22 Proceedings","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125522150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research on Post-processing Method of Topology Optimization Model","authors":"Han Gao, Lei Xu, Yuanhao Hu, Zhanglin Guo","doi":"10.14733/cadconfp.2022.367-371","DOIUrl":"https://doi.org/10.14733/cadconfp.2022.367-371","url":null,"abstract":"Introduction: Structural topology optimization is an effective structural optimization method, which has become a hot research topic in the field of finite element analysis. The variable density method is usually used to solve the structural topology optimization problem due to the advantages of less design variables and high efficiency. However, this method also has disadvantages such as network dependence and boundary diffusion which would increase the geometric complexity and optimization time cost. In addition, the optimization results often bring a gray transitional boundary, the ideal smooth boundary cannot be obtained by traditional method of curve approximation or curve fitting, and it is impossible to determine whether the boundary extraction and model reconstruction can be successful. At the same time, the optimization model needs to be attached to the grid during topology optimization, so it is unavoidable that the edge of the optimization result has a jagged boundary. This not only increase the manufacturing difficulty, but also increases the complexity of the structure and makes model reconstruction difficult. Aiming at the problems of boundary diffusion and jagged boundary existing in the topology optimized model based on the variable density method, a topology optimization post-processing method using the partition sensitivity filtering and the ordinary least squares is proposed. The partition weighted sensitivity filtering method is to divide the sensitivity filtering area into two parts, and use different weighting factors to weight the inner and outer areas respectively to remove the gray value to obtain a topology optimization structure with clear boundaries. The ordinary least squares curve fitting is to make the sum of the squares of the errors between the extracted boundary points and the fitting points reach the minimum value as much as possible, and the curve formed by the fitting points is an ideal fitting curve, which can make the jagged boundary become smooth. Some typical examples verify the effectiveness and feasibility of the method in suppressing boundary diffusion and solving jagged boundary problems under the conditions of single load, multiple loads and elements with different densities. By analyzing the model before and after post-processing, it is verified that this post-processing method can effectively obtain the topology optimization structure with clear and smooth boundaries, and the stress distribution is more uniform, which can reduce the difficulty of model reconstruction and manufacturing.","PeriodicalId":316648,"journal":{"name":"CAD'22 Proceedings","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127194648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CAD Refactoring and the Art of Computer Aided Design Model Maintenance","authors":"P. Rosso, J. Gopsill, S. Burgess, B. Hicks","doi":"10.14733/cadconfp.2022.339-343","DOIUrl":"https://doi.org/10.14733/cadconfp.2022.339-343","url":null,"abstract":"Introduction: Solid modelling is a common way to communicate and store geometric information. Solid models allow drafters to abstract complex constructs enabling them to be better understood and shared. Leveraging the computer-based nature of models a ords continuous improvement and re nement of models via version control and the ability to store the history of a model's evolution. The abstractions also support the use and reuse of part geometry resulting in more e cient, less error-prone and compressed product development cycles [9, 12]. However, with particularly long-life products, solid modelling still poses challenges for the long-term management of product data (among which geometry data). Kasik et al. [5] discusses a range of challenges for which two underlying themes of interoperability and reuse are evident. In addition to the two longer-term underlying themes, the type of abstraction applied by the engineer during the initial design of the CAD model will also impact current activities. For example, artefacts, such as intersections between surface geometry, can cause issue in the subsequent generation of Computer Aided Manufacturing (CAM) code and/or meshes for simulation. Given that geometry may be constructed with di erent design intent [7], it is important to understand which construction can be reused at a lesser cost. A consequence will be alleviating the drafter of further cognitive load, so that the drafter can continue to design in the way that works best for them or they believe works best. The subject of changing structure of a system/code base without a ecting its external behaviour is of great interest in programming and is referred to as refactoring. This eld also cites the need for refactoring to simplify source code for long-term maintenance and support, providing underlying performance enhancements introduced by new techniques and copying with the growing complexity of a project. All of which are analogous to the issues and aims of engineers/engineering management. Given the parallels in both the problem and solution, the authors propose refactoring as an approach to re-structure the relationships between design entities in a CAD model. The following sections discuss relevant literature in CAD, Technical Debt, Refactoring, and Graph Representation which provide the foundations for CAD refactoring. Throughout the sections the same artefact is represented in the context of the topic discussed.","PeriodicalId":316648,"journal":{"name":"CAD'22 Proceedings","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133419352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"3D Shape Generation by Iterative Interpolation of Meshes with Arbitrary Topology Using General Catmull-Clark Subdivision Surfaces","authors":"S. Lai, Jason Lai, Anastasia Kazadi, F. Cheng","doi":"10.14733/cadconfp.2022.88-92","DOIUrl":"https://doi.org/10.14733/cadconfp.2022.88-92","url":null,"abstract":"Introduction: An algorithm for fast construction of a smooth subdivision surface that interpolates the vertices of an arbitrary input mesh M is presented. The central idea of the proposed algorithm is to find the inverse A of the matrix A that calculates the limit points of M for the chosen subdivision scheme. However, instead of a costly matrix computation process, a technique to calculate A indirectly by representing it as an infinite series of matrices is developed. With this infinite series of matrices, one can construct an infinite iterative series of control points, which converges to a mesh whose subdivision surface interpolates the given input mesh M. Most importantly, this infinite iterative series of control points can be calculated locally based on the chosen subdivision scheme. Hence, the matrices A and A do not have to be actually constructed. They are simply used in a theoretical derivation to obtain the iteration formula. The construction of the interpolation surface is done basically by iteratively adjusting vertices of the given mesh until some given error tolerance is reached. The concept of iterative interpolation has been presented in the literature before [5, 6]. The main differences between our algorithm and existing approaches are fivefold: 1. Our algorithm is the first one that derives the iterative equation from the perspective of computing A. 2. The existence, convergence and uniqueness of A are guaranteed (the proof will be provided in the complete paper). 3. Our iterative interpolation algorithm, converging at an exponential rate, is a local process and does not involve costly matrix computation. Hence the new method is very fast and can handle meshes with large number of vertices. 4. Our algorithm does not require fairing in the construction process because solution to the above interpolation process is unique. 5. Although only the general Catmull-Clark subdivision surface is used here for deriving the iterative algorithm, the idea of the proposed algorithm works for other popular subdivision schemes as well.","PeriodicalId":316648,"journal":{"name":"CAD'22 Proceedings","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123377357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring the Potential of Tracking CAD Actions in Project-based Courses","authors":"Robert Celjak, N. Horvat, S. Škec","doi":"10.14733/cadconfp.2022.302-307","DOIUrl":"https://doi.org/10.14733/cadconfp.2022.302-307","url":null,"abstract":"","PeriodicalId":316648,"journal":{"name":"CAD'22 Proceedings","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126674582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Introduction of Accessorial Sketch Features for the Automatic Conversion of Mechanical Sketches into 3D Models","authors":"Masaji Tanaka, T. Asano, Chiharu Higashino","doi":"10.14733/cadconfp.2021.410-414","DOIUrl":"https://doi.org/10.14733/cadconfp.2021.410-414","url":null,"abstract":"Introduction. Sketches in the form of line drawings are commonly observed in magazines, books, manuals, etc. Sketches are also important for designers, especially mechanical designers, when they invent new ideas of products and their parts. The automatic conversion of sketches into 3D models will be advantageous for several applications. For example, it is expected that robots will be able to understand sketches by their converted 3D models in the future. In the last fifty years, numerous methods to automatically convert sketches into 3D models have been considered and developed. However, no real system for the conversion has been developed till now. We have been developing methods for the conversion of sketches into 3D models for approximately eight years. Consequently, we proposed a method as SFBCM (Sketch Feature-Based Conversion Method) to achieve this conversion [10-11]. In SFBCM, many issues have been still remained for developing the practical conversion system. In this paper, we attempt to handle chains, springs and screws in SFBCM. Generally, they are important machine elements, and often used in mechanical products and their parts. However, their sketches are tend to become symbolic because their shapes are complex. Fig. 1 shows examples of the sketches. Fig. 1(a) shows a sketch of chain. Fig. 1(b) shows a sketch of spring. Fig. 1(c) shows a sketch of screw with a hexagon head. In this paper, Accessorial Sketch Features (ACSFs) are introduced to SFBCM for handling sketches of chains, springs and screws. Generally, the shapes of them contain many kinds of repetitive features, so we define ACSFs from them.","PeriodicalId":316648,"journal":{"name":"CAD'22 Proceedings","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133529382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}