三维造型设计与工程图学的有效融合

随着计算机软硬件技术的普及和飞速发展以及制造业对二维计算机绘图以及三维设计造型技术日益增长的需求,在工程图学教学中有效地融入二维计算机绘图以及三维设计造型技术已显得尤为重要。论文介绍了北京理工大学在工程图学和三维造型创新设计方面“外挂式、分段式和融合式”三种模式的教学改革实践,并着重对如何将三维造型设计与工程图学有效地融合进行了论述。     

AutoCAD三维实体图形生成二维图形的实现

计算机辅助设计(CAD)是计算机应用技术中一项重要的技术。在CAD领域中,技术人员利用专门的计算机辅助设计软件来制作表现物体几何特征。AutoCAD是新一代计算机辅助设计软件,其功能强大,使用方便的特点在多种工程设计中得到广泛的应用。AutoCAD有强大的三维功能,可以在三维空间中先建立模型并从不同角度观察和处理模型,从三维模型可以生成各个方向的视图。本文主要介绍在AutoCAD中使用相关命令完成三维实体图形生成二维图形的方法。     

A Unified, Object-Oriented Graphics System and Software Architecture for Visualising CAD/CAM Presentations

Most object-oriented graphics systems (OOGS) either support general purpose graphics capabilities (drawing editors, ray tracing, etc.), or have targeted specific areas of computer graphics, for example, interface building, animation, and visualisation. However, the key concept in CAD/CAM graphics systems is that of presentations—pictures that convey information about products or parts of products. CAD/CAM graphics systems that create and manipulate presentations have specific graphical requirements that have not been addressed by existing OOGS. These requirements include the support of CAD/CAM concepts such as drawings, views and view-specific graphics, and layers, and the ability to allow external geometric modelers to be linked into the presentation. We describe an object-oriented presentation architecture that allows the application to describe the structure of the CAD/CAM presentation. This architecture provides a unified interface to drawings, views, layers and entities, and allows linkage to models created with an external geometric modeler, while isolating applications from details of the underlying traditional graphics rendering systems. It is our hope that this architecture provide the foundation for the architecture of next generation OOGS. We also present an implementation of this architecture and compare it to other OOGS.     

CATC — A Computer Aided Tolerance Control system

Computer utilization in manufacturing systems is increasing at a rapid rate. Developments thus far have been disjointed. Much work needs to be done in the area of integrating computer aided design and computer aided manufacturing (CAD/CAM). Tolerance control is an important component in the integration of CAD and CAM. Selection of design tolerances affects the build-ability of a product. The selection of manufacturing processes and sequence of processes affects process tolerance stacking. Unexamined process tolerance stacking leads to scrap and rework. A computer aided tolerance control (CATC) system is presented in this paper. This system is based on the tolerance chart technique. The CATC system is interactive and uses computer graphics for information display. The system can be used for computer aided process planning (CAPP) and for CAD/CAM integration.     

3D Icons and Architectural CAD

3D computer input has been a recurring challenge to engineers developing effective CAD systems. The approach adopted in this paper attempts to address a specific type of 3D input which is applicable to architecture and some engineering design tasks. In these processes, the object being designed is often an assembly of defined components. In a conventional graphics based CAD system these components are usually represented by graphical Icons which are displayed on the graphics screen and are arranged by the user. The system described here consists of 3D modelling elements which the user physically assembles to form his design. Each modelling element contains an element processor consisting of a machine readable label, data paths and control logic. The CAD system interrogates the elements. The logic within the element processors and the data paths are then used to interrogate other adjacent elements in the model. This system can therefore be considered as a "user generated""machine readable" modelling system. In an architectural application this provides the user with a system of 3D Icons with which to model and evaluate the built environment.     

Implementation of computer graphics exercises in freshman engineering graphics education

The rising application of computer-aided design (CAD) in the industrial environment has precipitated an interest in computer graphics for engineering education. At the University of Texas at Austin, a computer graphics laboratory has been established that is primarily dedicated to freshman engineering graphics education. The laboratory is currently equipped with eight Hewlett-Packard 2647 A intelligent graphics terminals. Five software modules have been developed to introduce the student to the graphics terminal and to demonstrate its capabilities for making engineering drawings. The modules permit the construction of line drawings, pictorials, graphs and charts on the CRT terminal without requiring any programming skill on the part of the student. The laboratory exercises have been successfully used by over 1000 engineering graphics students during the first two semesters of implementation. This paper describes the efforts to date in organizing and implementing this freshman computer graphics laboratory.     

计算时代工程图学之定位与建设思考

在2次《图学学科发展报告》基础上,专门讨论工程图学科学与学科的继承问题,探讨其在计算时代的定位与发展。梳理工程图学及画法几何的理论、方法和技术,揭示工程图学无歧义表达、完成工程计算中所隐含的严密理论及科学价值。剖析在计算时代工程图学呈现和渗透到计算机图形学的某些新形态。分析这2大图学分支的共性,特别是两者在图形思维和计算思维上对CAD的支撑作用。以此共性基础为核心,以工程应用为导向,以科学研究与人才培养为目标,探索建立多元思维融合的工程图学学科建设框架。     

Development of electrocardiographic teaching materials using an MC68000-based, interactive graphics microcomputer

Interactive computer-graphics methods of computer-aided design (CAD) have been applied to problems in physical science and industry for several years; however, at the present time CAD methods have not been widely used to solve similar problems in medical education. Electrocardiogram waveform fabrication for the production of teaching materials seemed to be a well-defined area for CAD application. The availability of inexpensive, 16/32 bit word, MC68000-based microcomputers (e.g. Apple, Macintosh) and interactive graphics software (e.g. MacPaint and MacDraw) seemed to provide the necessary tools to make this application. This paper describes the authors' initial experience (from June 1984 to March 1985) in developing and employing an interactive computer graphics routine to produce ECG teaching materials.     

试谈CAD和CATIA在飞机中的应用

随着计算机技术的快速发展,CAD和CATIA软件广泛应用于飞机设计。设计人员通过CAD和CATIA软件完成图纸设计,由计算机自动生成设计结果,可以快速显示图形,缩短设计周期和提高设计质量。     

基于计算思维的“计算机图形学”教学改革路径

“计算机图形学”与多个学科存在交叉情况,借助计算机使用数学算法与编程语言生成图形,可绘制出三维、二维图形。其主要包含四个部分,分别是建模、渲染、动画、人机交互。而计算思维则是指思维活动,基于计算机科学去求解问题、设计系统、理解人类行为,其在“计算机图形学”教学中的运用,也主要从以上几个部分入手。因此,基于计算思维进行“计算机图形学”教学改革具有良好的理论基础,为该课程的教学改革提供了指引,从而可以对教学内容进行优化设计、明确设计要点、打造教学流水线、培养学生的计算思维,进而提升“计算机图形学”教学的实效性。     

Current trends in computer graphics

A look at the trends in computer graphics is given by analyzing important areas that affect the progress of graphics like hardware, input and output devices for graphics, programming languages, systems developments and advances in techniques and algorithms for computer graphics. Then attention is given to new and expanded application areas for the future, as well as some problems that will persistently confront people working in graphics.     

A display package for CAD of control systems

A multi-access computer system has been installed at the Control Systems Centre of the University of Manchester Institute of Science and Technology. The application of this computer to research into the computer aided design of industrial control systems involved the connection of two keyboard display terminals to the system. The ARDS storage tube displays chosen had the advantages of being teletypewriter compatible and not requiring the connection of a satellite computer A graphics package for the entry and structuring of data derived from the stability analysis of control systems was required as soon as possible after the installation was commissioned. The initial package enabled data to be entered by program and then selected and plotted by keyboard requests. Translation, scaling, alteration of the method of plotting (with points or vectors) and the selection of different items for the display were all carried out by keyboard interaction For long term CAD work a more extensive graphics package was required, the specification was determined following feedback from users of the initial package. It provided additional facilities for graphic interaction, alphanumeric annotation of the displays, specialized drawing and data entry functions and the storing of any pictures built up by the user, as well as a more linked data structure. The structure and facilities of this package are described.     

Sketching 3D models with 2D interaction devices

The creation of a 3D shape using CAD tools, namely solid modelers, is difficult and time-consuming. Therefore, these systems are kept away from the conceptual phases of design, perhaps the most important in any product life cycle. The sketch is considered by many people as one of the fundamental techniques during a design's conceptual stages, as it enables high level design options to be explored at low cost. In general, this technique IS under-appreciated in the computer graphics world. In this paper, we present a system called IDeS that tries to combine simplicity and intuition while drawing, with the useful features of the solid modelers, for example, CSG operators.     

Interactive display of large solid models for walkthroughs

A new paradigm for designing complex engineering systems has emerged from computer graphics and CAD/CAM technology. Virtual design environments allow users to design and visualize all stages of the product. They not only free designers from the two dimensions of pencil and paper but also eliminate costly construction of physical mock-ups. We are developing the necessary technology for interactive walkthroughs of large mechanical and architectural models. This development includes model construction, display and interfacing with high-performance graphics systems and immersive technologies. Our ultimate goal is to create an environment where users will explore the complete model of a large design, such as a submarine, and verify that all constraints are satisfied in the same way they would a real one-by walking around in it. In applying our approach to a submarine storage and handling system model, we improved the overall frame rate by three to four times compared with rendering the polygonal B-rep. The online triangulation allows us to spend our rendering resources in the parts of the model significant for the current image. The overall system is currently being applied to large CAD models like submarines and fighting vehicles     

面向系统的计算机专业实践教学体系

深入理解计算机系统对提高计算机专业学生计算机应用系统设计能力具有重要意义。使学生深入理解计算机系统的重要途径之一就是面向系统的计算机专业实践教学体系建设。本文主要介绍东南大学面向系统的计算机专业实践教学体系建设探索经验,以供相关教学研究人员借鉴。     

Australian managers'' perceptions, attitudes and use of information technology

Survey data collected from 268 managers were used to examine the direct application and importance of Information Technology (IT), specifically computer application systems, to the jobs and skills that they possessed. The results showed that the majority of participants had access to and used at least the traditional computer applications, namely word processing, spreadsheets and presentation graphics. The influence of a training exercise on participants' attitudes towards specific systems and concepts was also examined. The result demonstrated a favourable shift in attitude as an outcome of the management training program.     

交互式图形程序库的设计方法

该文着重论述了在微型机上运用高级语言与Auto CAD系统开发交互式图形程序库的设计思想和方法,并对Auto CAD与高级语言程序的连接,数据交换等重要枝术问题的软处理方法,作了详尽介绍。可广泛地使用于桥棵.土建.岩土机械等多种领域的计算机辅助设计中。     

PC Hardware Developments and CAD Software

Not too long ago, PC-based CAD was used only for simple drafting functions by companies that couldn't afford anything better. Now it has become a force driving the CAD industry, and manufacturers of traditional mini and mainframe-based systems are playing their respects by marketing PC-CAD systems of their own. AS much as anything else, new computer and graphics hardware developed in the past few years has made this shift possible.