摘要:System optimization plays a crucial role in developing VR system after 3D modeling, affecting the system's Immersion and Interaction performance enormously. In this article, several key techniques of optimizing a virtual mining system were discussed: optimizing 3D models to keep the polygon number in VR system within target hardware's processing ability;optimizing texture database to save texture memory with perfect visual effect; optimizing database hierarchy structure to accelerate model retrieval; and optimizing LOD hierarchy structure to speed up rendering~
摘要:An enhanced system architecture of Web-based product structure and configuration management system along with its, functions are is presented. The key techniques, such as construction of object models of product structure and product configuration, hybrid approach method in product configuration management, sharing and integration of heterogeneous product data, integration with other sub-systems, are discussed too. A prototype system is developed by J2EE technology.
摘要:1. The 13th International Conference in Central Europe on Computer Graphics, Visualization and Computer Vision'2005, University of West Bohemia, Campus-Bory Plzen (very close to Prague, the capital of the Czech Republic)Czech Republic, January 31 - February 4, 2005. http://wscg.zcu.cz, skala@kiv.zcu.cz
摘要:The 11th International Conference on Geometry and Graphics (ICGG) decided that Prof. Hellnuth Stachel(Austrial) is the winner of the Steve Slaby Award 2004 for his outstanding scientific and educational work.
摘要:Part and Draft modules of SolidEdge are used to construct 3D solid models and generate part drawings, while ActiveX Automation of VB is used to access engineering database files to realize dimension-driven modification of the designed parts. Moreover, VB plays the enabling role of integrating all work processes of gear pump design, resulting in a comprehensiveCAD system.
摘要:In net-based collaborative design environment, design resources become more and more varied and complex. Besides common information management systems, design resources can be organized in connection with design activities. A set of activities and resources linked by logic relations can form a task. A task has at least one objective and can be broken down into smaller ones. So a design project can be separated into many subtasks forming a hierarchical structure. Task Management System (TMS) is designed to break down these tasks and assign certain resources to its related task nodes. As a result of decomposition, all design resources and activities could be managed via this system. Based on this idea, we realized a TMS which manages collaborative resources in web environment.
摘要:A new method as a post-processing step is presented to improve the shape quality of triangular meshes, which uses a topological clean up procedure and discrete smoothing interpolate (DSI) algorithm together. This method can improve the angle distribution of mesh element, while keeping the resulting meshes conform to the predefined constraints which are inputted as a PSLG.
摘要:The design of the coohng system of injection molds directly affects both productivity and the quality of the final part. Using the cooling process CAE system to instruct the mold design, the efficiency and quality of design can be improved greatly. At the same time, it is helpful to confirm the cooling system structure and optimize the process conditions. In this paper, the 3D surface model of mold cavity is used to replace the middle-plane model in the simulation by Boundary Element Method, which break the bottleneck of the application of the injection molding simulation softwares base on the middle-plane model. With the improvements of this paper, a practical and commercial simulation software of injection molding cooling process named as HsCAE3D6.0 is developed.
摘要:In this paper, firstly, a mathematical model for a specific kind of welted bifurcation is established, the parametric equation for the intersecting curve is resulted in. Secondly, a method for partitioning finite element meshes of the welted bifurcation is put forward, its main idea is that developing the main pipe surface and the branch pipe surface respectively, dividing meshes on each developing plane and obtaining meshes points, then transforming their plane coordinates into space coordinates. Finally, an applied program for finite element meshes auto-generation is simply introduced, which adopt ObjectARX technique and its running result can be shown in AutoCAD. The meshes generated in AutoCAD can be exported conveniently to most of finite element analysis soft wares, and the finite element computing result can satisfy the engineering precision requirement.
摘要:The algorithm is divided into two steps. The first step pre-locates the blank by aligning its centre of gravity and approximate normal vector with those of destination surfaces, with largest overlap of projections of two objects on a plane perpendicular to the normal vector. The second step is optimizing an objective function by means of gradient-simulated annealing algorithm to get the best matching of a set of distributed points on the blank and destination surfaces. An example for machining hydroelectric turbine blades is given to verify the effectiveness of algorithm.
摘要:The system is based on the globally shared product model conforming to VRML Standard, and uses SmarTeam (PDM) system to integrate and encapsulate CAD, CAE and other application software for product development. The system takes sugarcane harvester, mobile telephone design analysis and evaluation as an example, and utilizes fuzzy evaluation principle to evaluate the design and simulation analysis results for decisions making. The platform provides a collaborative intelligent environment for the design of products, aiming at integrating people, process and data in the virtual product development. The multi-layered system architecture provides capability for KBM and conception innovation design process with a single unified data and process model so as to achieve true process streamlining and data integrity throughout the entire product development lifecycle, and hence improves enterprises efficiency.
摘要:Internet has gradually demonstrated more and more superiority in modern education system. The intelligent online drawing platform based on net will provide learners with a studying environment without limitation in time and space. Based on the theory of graphics, this paper developed an intelligent online drawing platform (IODP) with Java through analyzing the teaching character of descriptive geometry. IODP developed not only has a flexible drawing environment with the function of mutual drawing, but also is able to judge the drawing made by students and give feedback at the same time. This platform gives an effective way for Internet education on engineering graphics.
摘要:Concerning the demands in networked collaborative innovative design, a knowledge-based collaborative design model is introduced the model of knowledge integration along with its relevant supporting techniques are presented. After illustrating the general knowledge search paradigm, a kind of dynamic user model is proposed to improve knowledge search efficiency. At last a short introduction of the system's implementation is described.
摘要:The flight control system designer is increasingly concerned with the problem of providing adequate stability of the elastic modes of the flight vehicle. The problem of stabilizing bending modes can be solved by the use of different bending filters. But continuously changing behavior of the elastic modes frequencies makes it impossible to suppress the elastic modes. In this paper, adaptive tracking filter is used to solve this problem. Where it can track the frequency of predominant oscillatory component of its input signal and automatically adjust the shaping characteristics as a function of this frequency. Simulation results are presented to show the frequency tracking accuracy and response of the flight launch vehicle, which are based on the assumption that, only first bending mode is selected at a time. Comparison with the second order band pass filter is carried out in order to emphasis the effectiveness of this design methodology.
摘要:Most injection molded parts are three-dimensional, with complex geometrical configurations and thick/thin wall sections. A 3D simulation model will predict more accurately the filling process than a 2.5D model. This paper gives a mathematical model and numeric method based on 3D model, in which an equal-order velocity-pressure interpolation method is employed successfully. The relation between velocity and pressure is obtained from the discretized momentum equations in order to derive the pressure equation. A 3D control volume scheme is employed to track the flow front. The validity of the model has been tested through the analysis of the flow in cavity.
摘要:The current 3D CAD/CAM system, both research prototypes and commercial systems, based on traditional feature modeling are always hampered by the problems in their complicated modeling and difficult maintaining. This paper introduces a new method for modeling parts by using adaptability feature (AF), by which the consistent relationship among parts and assemblies can be maintained in whole design process. In addition, the design process, can be speeded, time-to-market shortened, and product quality improved. Some essential issues of the strategy are discussed. A system, KMCAD3D, by taking advantages of AF has been developed. It is shown that the method discussed is a feasible and effective way to improve current feature modeling technology.
摘要:Due to the increasing complexity of products and for the distributed product development, more closely collaborative work among designers is required. A collaborative assembly planning approach is proposed to support assembly planning in a networked environment. The working procedure is depicted and the key techniques including collaborative-planning-oriented assembly decomposition modeling, assembly assignment modeling, and sub-plans merging are addressed. By incorporating visual models at client side with assembly application models at server side, a web-based supporting environment for collaborative assembly planning has been developed using VRML and Java-EAI techniques. A case study is given to illustrate the feasibility and validity of the idea.
摘要:Based on long-time research on vocational teaching cube theory in graphics education and analyzing on the intellectual structure in the process of reading engineering drawing, the graphics intellectual three-dimensional model, which is made up of 100 cubes, is founded and tested in higher vocational graphics education. This system serves as a good guidance to the graphics teaching.
摘要:The changes of design methods and manufacturing techniques have brought new requirements for engineers in enterprises, and therefore brought a challenge to the traditional teaching system of mechanical major courses. A new teaching system based on three-dimensional design to cultivate modern engineers with solid specialty bases and high creativity in a wide range of fields is presented.
摘要:A brief historical introduction of researches on perspective in ancient China is presented,this paper studied and discussed the perspective theory or Zong Bing (宗炳) in the 5th century of China, including Zong Bing and this An introduction to Landscape Painting, and its mathematical basis, drawing ideas of Zong Bing as well.
摘要:To find starting points for all the intersection curves, one of the surfaces is subdivided into some small surface patches. Based on a correlative algorithm of computing the minimum distance of two surfaces, the intersections of every patch with another surface are detected, and starting points are calculated by dichotomy. This algorithm shows superior efficiency in the computational complexity and number of iterations needed. It can be used to determine exact starting points on all possible solution curves between any kinds of parametric sculptured surfaces.
摘要:According to the requirements of designing V-groove pulley transmission, an application development based on AutoCAD environment and using AutoLISP language is presented. As an example of effective solution for CAD application, the CAD system for V-groove pulley transmission is established.
摘要:CAD process for structure design of box culvert is introduced. It follows the traditional way of culvert design. All working conditions of culvert are taken into account. It can generate load diagram, bending moment diagram and bending moment envelope diagram for a single-hole, double-hole or triple-hole box culvert .That is to say, the whole CAD process for the box culvert structure design is realized with the self-developed system. It has been used to accomplish several projects in China and the results are satisfactory.
摘要:One of the open issues in principle scheme design of mechanical systems is principle representation,which not only outlies the physical principles,but also facilitates the design synthesis.An energy-based approach to represent principle scheme design is proposed.Firstly,an energy interaction model of mechanical systems is established and an intermediate model is derived,in which principle scheme design is transformed into solving the energy functions of system.Then the energy functions are modeled with the language of bond graphs,and principle representation for componenyts is presented.Finally,characteristics of the developed representation approach are analyzed and a design example of gate drive system is given to demonstrate this approach.
摘要:Currently many enterprises have established some independent application systems such as CAD,CAPP,CAE and so on.Enterprise information integration makes these information islands connected,and thereby forms a uniform enterprise-wide information environment,First this paper discusses the main research contents of enterprise integration.Then the author introduces an Internet-based configurable and open information integration framework,and presents a multi-tier integration architecture based on reusable component,Finally a development case of enterprise integration framework is introduced.
摘要:Virtual assembly is a Virtual Reality(VR) based engineering application which allows engineers to evaluate,analyze,and plan the assembly of mechanical systems,To model the virtual assembly process,new methodology must be applied.Based on the idea that the virtual assembly system is an event driven system,the interactive behavior and information model is proposed to describe the dynamic process of virtual assembly.Definition of the objectoriented model of virtual assembly is put forward.
摘要:This paper introduces the current situation of domestic furniture production as well as world furniture CAD products,puts forward the necessity of developing a dedicated CAD system_WFCAD and its main functions,It analyzes in detail the applied technology and key techniques,including geometric modeling,assembly,joint design,database linking and management.The application of WFCAD in furniture manufacturing enterprises and its further improvement are outlined.
摘要:This paper presents an approach which enables surface modelling,mesh generation and the Finite Element(FE) analysis to be integrated together to simulate superplastic forming process for complex shaped components.Techniques have been developed to generate an FE mesh over non-four-sided surface areas,the boundaries of which are Bezier curves of arbitrary degree,using a consistent expression.Theoretical evidence is given to determine the number of Bezier triangular patches required for accurately re-constructing die surfaces within a commercial FE solver.The developed techniques have been successfully used in determining the process parameters for forming a 3D rectangular box.
摘要:Analyzed the issues of stability of workpiece during clamping and machining,Discussed classification of the stability problem according to the forces acting on the part in the commonly used machining processes;gave the methods of calculating clamping force and measures to guarantee the stability of workpiece in the feature-based fixture planning design system.
摘要:To avoid the shortcomings of many Web education systems that look like Web books,a true Web multimedia Engineering Graphics courseware is developed to explore the method and techniques of 2D animation with text,buttons,and graphics merged together,For speeding up the transmission and download,data compression and interactive approach are introduced.