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31 October 2012, Volume 33 Issue 5 Previous Issue    Next Issue

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A survey on content-oriented interpretation of engineering drawings Lu Tong, Cai Shijie 2012, 33(5): 1-12.  Abstract ( 67 )   PDF (268KB) ( 299 )   A comprehensive survey on the automatic recognition and understanding methods for engineering drawings is proposed. Target of interpretation of engineering drawings lies on automatic extraction of explicit descriptions (e.g., graphical primitives, engineering symbols, engineering entities) and implicit semantics behind the drawings. Vectorization, recognition of engineering symbols and engineering entities are analyzed systematically. Based on these, performance evaluations and benchmarks are also proposed. Finally existing difficulties and future research are discussed. Related Articles | Metrics

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NURBS surface fairing method Yin Xiaokui, Li Qimin, Ye Zhongquan, Jiang Hengheng 2012, 33(5): 13-18.  Abstract ( 127 )   PDF (276KB) ( 474 )   NURBS curve and surface fairing treatment is a very important issue in CAD/CAM. On the basis of a study of several common methods in NURBS surface fairing, aiming at the insufficiency of the existing fairing algorithm in multi-scale features coexisting surface fairing, a thought of combining anisotropic wavelet into surface multi-resolution analysis is put forward by use of the anisotropic wavelet’ advantage in the expression of high-dimensional information, which can be applied into NURBS surface fairing to achieve the preservation of surface features. Related Articles | Metrics

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Research on the strategy of feature displacement for cylinder sweeping feature in finite element fields Liu Xiaoping, Li Dan, Jin Can, Li Shujie 2012, 33(5): 19-23.  Abstract ( 86 )   PDF (401KB) ( 180 )   In the finite element analysis, the calculation of the model with overcomplicated geometric attributes will lead to a huge cost of computing resources. As some kind of geometric attributes have little impact on the calculation result, simplification of those attributes will greatly increase the computing efficiency. In this paper, the relationship between sweeping path’s curvature and mesh diametric is researched and the proper displacement strategy of cylinder sweeping feature which is prevalent in model is explored. Feature displacement reduces the cost of computing resources on the premise of a certain analysis concise. Finally, a simulation experiment focused on finite element thermal analysis is executed to verify the validity of the conclusions. Related Articles | Metrics

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The 3D modeling and analysis of hyperbolic paraboloid based on the spatial affine point ranges Jiang Xiaohong, Song Yan 2012, 33(5): 24-27.  Abstract ( 85 )   PDF (318KB) ( 181 )   This article constructs three-dimensional hyperbolic paraboloid based on spatial affine point ranges using the computer 3D software. From the projection in different directions on hyperbolic paraboloid，a series of projection drawing in different directions and angles of the hyperbolic paraboloid can be acquired. The characteristics of the projection drawing of the hyperbolic paraboloid are understood more directly and clearly from these projections. By using a number of planes of different locations to cut the hyperbolic paraboloid and by analyzing and observing the trend of intersection lines, several conclusions of regularity are obtained. Related Articles | Metrics

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The one-sheet hyperbolic formed by two projection point ranges in space Liu Fuping, Ding Yong 2012, 33(5): 28-31.  Abstract ( 84 )   PDF (321KB) ( 234 )   The One-Sheet Hyperbolid can be formed by connecting the correponding points of projection point ranges with two intersection lines as the basis in a space. When one line of them is moved to a new position, the One-Sheet Hyperbolid will generate change in a certain pattern. Through a systematic analysis to the shape of its intersection lines, it is for the first time to put forward the existence of the parabola-type intersection line in the One-Sheet Hyperbolid. Simplification of the drawing of projection point ranges provides theoretical support to further application of CAD software to automatically produce the Hyperbolid. Related Articles | Metrics

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Web-based symmetry error evaluation and its visualization Zhai Xujun, Zhuo Shenghua, Wang Junze, Zhang Xiaoping 2012, 33(5): 32-37.  Abstract ( 95 )   PDF (643KB) ( 193 )   By taking the symmetry error for flatness to flatness as an example, the specific web-based method for the visualization of tolerance of form and position is discussed and the mechanisms of communication and interaction theory between VRML and Java are clarified. Simultaneously, with VRML as the 3D displaying platform and Java Applet as the controlling core, the visualization of symmetry error for flatness to flatness is presented as an instance. Users can directly observe the position of the reference central plane and the distribution of measure points in the screen. So, it provides a foundation for amending unqualified parts and improving follow-up process. Related Articles | Metrics

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Study on microscopic image measurement technique of fluidic particles Zhang Yanbin, Li Weilin 2012, 33(5): 38-43.  Abstract ( 51 )   PDF (595KB) ( 289 )   For the requirements of moving particles image measurement in microscopic environment, the measurement system is built, and the measurement chip based on MEMS technology is developed. On the base of analyzing the characteristics of microscopic images of moving particles, the image measurement methods based on the particle moving characteristic are put forward, thereinto target extraction arithmetic based on datum frame is advanced, which solves the problem of aim division of moving particles, and according as the degradation model of image motion blur, the image blur restoration is realized. At last the example of a debris in lubricating oil is given, the calculating result validates the efficiency of analyzing method for moving particle in the article. Related Articles | Metrics

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Automatic wire harness pre-assembly planning method based on engineering semantic constraints Liu Xiaoping, Li Zhongze, Xu Benzhu, Zhu Jiman, He Honglin 2012, 33(5): 44-50.  Abstract ( 73 )   PDF (302KB) ( 237 )   Wire-harness pre-assembly is an important step in wire harness production. This paper presents an automatic wire harness pre-assembly planning method by means of summarizing engineering semantic constraints in wire harness technological design and establishing assembly incidence graph. This method realizes planning wire harness pre-assembly sequence through main-connector selection, largest subassembly extraction and engineering semantic constraints detection without users’ alternation. The practical application examples show that the automatic wire harness pre-assembly planning method presented in this paper is effective and feasible, and it can solve the assembly sequence planning problem in large wire harness graphs. Related Articles | Metrics

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A line clipping algorithm against circular window based on intercepts Ren Honghai, Guo Fajun, Wang Yanjuan 2012, 33(5): 51-56.  Abstract ( 101 )   PDF (186KB) ( 243 )   Based on the premise that the center of circle is the coordinate origin, when the two endpoints of a line segment are outside circular window after the line segment that both endpoints are outside any boundary of circumscribed-square or at least one endpoint is inside circular window is determined: if the absolute value of the intercept on x coordinate axis or y coordinate axis is less than or equal to radius r, the intersection can be identified quickly; otherwise, the intersection is identified according to point-line relation and comparison of coordinates of intersections when the tangent and the line segment separately cross the edge of circumscribed-square. The new algorithm can quickly calculate the intersections between a line segment and circular window, avoid the complicated auxiliary operation and further improve the clipping efficiency. Related Articles | Metrics

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A five-point binary approximating subdivision scheme for curve design Zhuang Xinglong, Tan Jieqing 2012, 33(5): 57-61.  Abstract ( 68 )   PDF (182KB) ( 218 )   A binary five-point approximating subdivision scheme is described. The generating polynomial method is used to investigate the uniform convergence and Ck -continuity of this subdivision scheme. The subdivision scheme generates a family of Cn (n=1, 2,3,4,5) limiting curves for certain range of tension parameter μ and a C7 limiting curves forμ=9/256. Some examples of the subdivision curve design are given to demonstrate the efficiency of the scheme. Related Articles | Metrics

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Research on the continuity conditions for CE-Bézier surfaces Hu Gang, Ji Xiaomin, Shen Xiaoqin, Song Weijie 2012, 33(5): 62-67.  Abstract ( 125 )   PDF (288KB) ( 249 )   Focusing on the problem that the engineering complex surfaces can not be described by using a single cubic extension Bézier (CE-Bézier) surfaces with multiple shape parameters, the continuity conditions of CE-Bézier surfaces are proposed. Following the analysis of basis functions and terminal properties, the unique property of CE-Bézier curves is investigated and the corresponding conclusion that a CE-Bézier curve can be defined by many different groups of control points and shape parameters is also obtained. And then, the geometric model of CE-Bézier surfaces is constructed and the condition of G1 continuity between two adjacent CE-Bézier surfaces in u and v directions is derived and simplified by choosing the control parameters properly. The modeling examples illustrate that the continuity condition of CE-Bézier surfaces can be widely applied to the complex surfaces modeling system. Related Articles | Metrics

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ArcGlobe-based 3D virtual digital campus visualization and modeling Mou Naixia, You you, Yue Hanqiu, Liu Wenbao, Gan Xinping, Yan Fangfang 2012, 33(5): 68-72.  Abstract ( 97 )   PDF (813KB) ( 412 )   As a microcosm of digital city and fundamental platform of virtual campus, 3D digital campus constructions are booming with a new climax. In this paper, ArcGlobe (a component of ArcGIS) is employed to simulate the 3D campus. By taking Qingdao campus of Shandong university of science and technology as a case, various data sources and their corresponding processing methods are analyzed, specific technological route of whole digital campus simulation is proposed, the creation of 3D digital terrain modeling in different area with different surface rolling is given, the way to create 3D building modeling specially is emphasized. Also, LOD and dynamic texture match are illustrated since they raise signally the speed of loading and drawing. The experiment presented in this paper is proved to be more reasonable and efficient in 3D digital campus construction. Related Articles | Metrics

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The implementation of multi-channel three-dimensional simulation system based on vega prime Zhao Bisha, Feng Kaiping, Luo Lihong 2012, 33(5): 73-77.  Abstract ( 83 )   PDF (312KB) ( 276 )   The software system of 360 Degree Virtual Experience Zone, which was presented in Guangzhou Case Pavilion of Expo 2010 Shanghai China, is taken as a prototype in order to describe the implementation of multi-channel three-dimensional simulation system based on Vega Prime. First, the system is outlined with the description of the implementation principle and development process, and then the implementation of system is discussed with emphasis on the three main steps which are three-dimensional modeling, simulation system building and scene editing, demonstration effect and technical points in the stand-alone presentation are presented with the comparison of the new system and the old one. Related Articles | Metrics

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Research and development of hydro-generator units virtual installation based on X3D Liu Jianguo, Zhao Linming, Wang Liying 2012, 33(5): 78-82.  Abstract ( 72 )   PDF (438KB) ( 334 )   Because the structure of hydro-generator units is complex, students and specialized technical personnel may face certain difficulties in understanding the structure and installation process of hydro-generator units. To solve this problem, on the basis of 3D modeling of the hydro-generator units with Pro/E, Xj3D kit、Java and Java3D are studied to realize the dynamic interaction of Virtual scene: 3D modeling is successfully interacted into Virtual scene X3D, and the virtual installation of X3D is finally realized. Practical application shows that virtual installation system of the hydro-generating unit has higher application value in teaching and the training of technical personnel. Related Articles | Metrics

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Scientific confirmation of perspective of Chinese traditional painting Wu Mingyun 2012, 33(5): 83-88.  Abstract ( 88 )   PDF (422KB) ( 306 )   Perspective of Chinese traditional painting is beyond the stripshow and perspective areas of the western painting. The perspective effect can increase the reverse perspective distortion from awareness. According to perspective analysis based on " Tortoise patterns ", the human eye bare perspective and the axonometric perspective (WMY) are correlated and continuous. A scientific analysis and research is conducted to the perspective effect of Chinese traditional painting according to stadia subsections as well as to the influences of Chinese human cultural factors. A new understanding of Chinese traditional painting perspective is done from new view angle and by new methods, and a scientific construction of Chinese traditional painting perspective is provided according to new concepts and new theories. Related Articles | Metrics

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The feature recognition of 3D model for NC processing time forecasting Wang Ning, Xi Ping, Zhang Baoyuan 2012, 33(5): 89-93.  Abstract ( 74 )   PDF (497KB) ( 249 )   Since features of NC machining structural part have obvious hierarchical distribution nature, a method based on the relationship of adjacent faces is provided. The faces of the part are combined into base faces and constraint faces. Then with the concave-convex relationship, these faces are combined into layers. The layer is used as the base of feature recognition. By recognition and combination of layers, machining features are recognized, and parameters of them are extracted. Finally the machining time is computed with the parameters of NC machining tool and the features. Related Articles | Metrics

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The module design of three-dimensional CAD-document fast packing based on SolidWorks Luo Yufeng, Chen Xu, Li Yuanshan 2012, 33(5): 94-98.  Abstract ( 73 )   PDF (512KB) ( 287 )   To ensure the relevant three-dimensional CAD document to be effectively packed, the module of three-dimensional CAD-document fast packing is designed in Visual C++ development environment, which adopts SolidWorks API and synchronous development model of DLL. The module consists of four components: SolidWorks addin plug-in components, user interface components, assembly traversal components, data files released components, which can quickly send assembly document and all sub-assemblies, parts, drawings to the specified directory. Related Articles | Metrics

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Sphericity error evaluation based on a modified particle swarm optimizer using dynamic inertia weight Hu Jie, Cui Changcai, Huang Fugui 2012, 33(5): 99-103.  Abstract ( 83 )   PDF (219KB) ( 244 )   To precisely evaluate the form error of sphere, a modified particle swarm optimizer (PSO) using dynamic inertia weight based on four kinds of mathematical models of sphericity error evaluation is proposed to calculate two groups of data. The dynamic inertia weight is changed in every iteration according to the particles’ positions and the objective function in this optimizer. A comparison is made among this optimizer, the basic PSO, the least square method, the genetic algorithm and an improved particle swarm optimizer. The experimental results show that, compared with other methods, error gained by the modified PSO using dynamic inertia weight based on the mathematical model of the sphericity error under the condition of minimum zone is the least. For the first group it only takes about 50ms to converge and the iteration times are just about 30. The speed of convergence of the second group is also very rapid. Repeated tests indicate that the algorithm has high stability. Therefore, the algorithm can evaluate the sphericity error precisely and rapidly. Related Articles | Metrics

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The approximation to sphere with polyhedrons and its application to industrial design Huang Sui, Han Chunming 2012, 33(5): 104-108.  Abstract ( 71 )   PDF (297KB) ( 446 )   Sphere is one of the modeling languages frequently used in industrial design, but because of some need or restrictions, a sphere is often approximately expressed as a polyhedron. Some criterions of sphere's approximation with polyhedron and ways to improve the effects are proposed, the applications of which in the industrial design are discussed as well. Finally, some examples are presented. Related Articles | Metrics

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Optimization and research of fire fighting truck’ layout design based on ergonomics Liu Xiaoxia, Wang Xiaoping, Yang Yanpu, Wang Shuxia 2012, 33(5): 109-113.  Abstract ( 84 )   PDF (717KB) ( 185 )   The layout design of fire engine equipments directly affects firefighters' battle efficiency and their personal safety and health. On the basis of analyzing the man-machine engineering of fire engine's equipments layout space, combined with the arrangement principles, "human" factors and the type of fire engine's equipments, this paper proposes design principles of space design and equipment layout. Taking certain type of truck equipment layout design as an example, the improved scheme is verified reasonable by the visual and reachable domain analysis on layout with the application of the JACK software. Related Articles | Metrics

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The analysis and extraction of interface geometric information of tube metal structure Mao Xin, Ma Mingxu, Zheng Zhijia 2012, 33(5): 114-119.  Abstract ( 92 )   PDF (465KB) ( 178 )   Based on the analysis of the domestic production of metal industry, the processing of plate thickness of the tube metal structure is studied. The theory, method and steps of extracting the interface geometry information are put forward. The accurate extraction of the interface geometry information and the accurately processing of the plate thickness are realized by the methods of diagram, analytical modeling and the system development based on the numerical method. The method and steps can be used in similar cases. The research result can be applied to improve product quality and reduce production cost of tube metal structure. Related Articles | Metrics

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Feature-based product information application mode Wei Yibin, Tian Ling, Wu Yuanhao 2012, 33(5): 120-126.  Abstract ( 81 )   PDF (372KB) ( 203 )   Enterprise information management system has been greatly popularized. As time goes by, many information management systems have accumulated a large amount of data. This paper presents feature-based product information application mode to make better use of this data. Some specific problems in enterprise information management can be solved by feature extraction and feature operation. Finally, the information system of a specific equipment research and development center is taken as an example to illustrate the application of this mode. Related Articles | Metrics

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Design and realization of the drawing contest management system Zhao Jianguo, Wei Qingfeng 2012, 33(5): 127-131.  Abstract ( 73 )   PDF (299KB) ( 206 )   To organize ‘Gaojiao cup’ drawing contest efficiently and orderly, a new drawing contest management system is developed by using VB6.0 programming language, Access database, Excel and Crystal Reports tool. The system has batch input function including image information by using Windows API and Excel VBA, and has batch output and printing function by using Crystal Reports tool. The design and realization of the system will provide a reference for other similar requirements. Related Articles | Metrics

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Propagation analysis of engineering change based on digraph Fang Yongze, Xie Shutong, Chen Jianhai, Wu Xu 2012, 33(5): 132-136.  Abstract ( 65 )   PDF (280KB) ( 216 )   A novel propagation analysis approach of engineering change based on digraph is proposed, and the corresponding software system for the analysis of engineering change is also developed. Firstly, this paper analyzes several main issues in the engineering change problem, such as the propagation, coordination, ending points, and control of the parts change. Then the propagation model digraph and propagation digraph are introduced. Furthermore, the data structure and the generating algorithm of the propagation model graph are developed along with the corresponding software system. In this approach, the propagation digraph is used to record not only the propagation range of the parts change, but also the change scheme and the impacts evaluation of the parts. With the proposed approach and the corresponding software system, it is more efficient and objective to analyze and evaluate engineering changes. Related Articles | Metrics

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Study and practice on teaching system of mechanical drawing centered on coordinated development of knowledge, ability and quality Tang Xiaochu 2012, 33(5): 137-140.  Abstract ( 62 )   PDF (203KB) ( 227 )   Research background and the research aim on the topic is elaborated from the universal situation of teaching mechanical drawing in college undergraduate. Ａpersonnel training system on mechanical drawing teaching is proposed which takes the students as the main body, takes the teacher as the dominator and develops students’ knowledge, ability and quality in coordination. This system includes a research on the teaching knowledge system by interdisciplinary fusion of mechanical drawing and computer graphics, the construction of network and multimedia teaching platform based on the merging of the theory and practice and the exploration of educational model. It also includes a project-driven and research-type test pattern reform practice of independent proposition by students. A three-year pioneering teaching practice in experimental classes shows that the system is scientific and efficient. The research results have obtained promotion and application. Related Articles | Metrics

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A system of engineering drawings and BOM management based on design environment Luo Nianmeng, Xiao Zuan, Zhu Lin 2012, 33(5): 141-146.  Abstract ( 74 )   PDF (329KB) ( 182 )   With the wide use of paperless production model, the management of numerous data of engineering drawings and BOM becomes an important research field. A system of engineering drawings and BOM management based on design environment is introduced. The system takes whole parts or whole products as dividing units and integrates them directly in CAD system based on database technology. It avoids the tedious management process of softwares such as PDM and PLM etc and it is more convenient for designer to use. The system takes engineering drawings as data bases and can generate BOM reports in several formats. The reliability and effectiveness of this system is verified in a practical application on enterprises production. Related Articles | Metrics