一个专用CAD系统中数据通信的设计与实现

CAD系统软件规模的不断膨胀和扩大,促使越来越多的计算机技术参与到CAD系统的设计和实现上来。CAD系统的模块化设计要求实现各模块之间的数据通信。该文利用进程通信机制实现了一个专用CAD系统内部各模块之间的数据通信,并详细介绍了数据通信实现的设计、结构和算法。系统平台为windows2000,开发工具为VisualC++6.0。     

网络时代智能CAD技术的开发应用

分析了网络时代CAD技术的发展和应用CAD技术 ,论述了当前通用CAD系统存在的不足、制约CAD深层次应用的因素和面向设计过程的智能CAD系统开发的关键技术 ,提出了网络时代基于领域产品模型的CAD系统结构。     

支持协同工作的工程CAD/CAM系统研究

首先介绍了计算机支持协同工作的概念和原理，以及CAD／CAM系统发展趋势；然后对支持协同设计的工程CAD／CAM系统的支撑环境、系统协同模型、实时协同设计过程进行了相应的分析与说明；最后设计出一个支持协同设计的工程CAD／CAM系统模型，并在一个纺织面料CAD系统中得以应用。     

基于参数化技术的变压器CAD系统

基于参数化技术 ,设计实现了变压器 CAD系统 ,其中参数化绘图采用 Auto CAD的 VBA进行设计 ,并实现了由 VB到 Auto CAD的 VBA的连接驱动。介绍了 Auto CAD Active X、VB与 Auto CAD间的连接等系统的关键技术。     

CAD文件的网上发布、管理系统设计与实现

CAD系统作为辅助制造设计的工具已经广泛应用于机械、电子和纺织设计等领域。但在Internet高速发展的今天其信息共享能力差的弱点暴露无遗。完善CAD文件的网上发布、管理能力是提高CAD系统的信息共享能力的关键。本文在分析CAD文件格式和发布方法的基础上设计了一个面向Internet的文件发布管理系统模型,并以CAD辅助教学网站的管理为例说明系统的可行性。     

一个小型机上的LSI CAD系统的方条

大规模集成电路(LSI)的计算机辅助设计(CAD)技术是发展LSI必不可少的工具,建立一个以CAD数据库为中心的LSI CAD系统将会更有效地发挥CAD技术的作用。本文介绍的是一个小型机上的LSI CAD系统—TCADS,它以CAD数据库TCD-1为中心,包括逻辑模拟、电路模拟、版图的辅助设计和辅助制版、版图的检查等若干个子系统。文中提出了系统的设计目标和设计思想,然后介绍了系统的结构,最后简述了初步实施的情况。     

GAD技术发展趋势与机械制造企业对策

一、引言 并行工程、即时生产、精益生产、敏捷制造和虚拟现实等先进制造技术和系统都与CAD技术的发展与应用密切相关.CAD系统中出现了许多先进技术,如变量化技术、虚拟产品建模技术等.目前,CAD技术的研究热点有计算机辅助概念设计、设计知识的管理及利用、计算机支持的协同设计、新的设计方法和设计理论研究等.随着互联网的普及,集成化、智能化、协同化成为CAD技术新的发展特点,使CAD技术得到更广泛的应用,发展成为支持协同设计、异地设计和信息共享的网络CAD.     

钢结构CAD系统自动布置设计研究

结构布置设计是钢结构CAD系统连接模型设计与结构分析等部分的桥梁。本文以钢结构CAD系统的研究为背景 ,探讨了钢结构CAD系统的计算机布置原理和方法。本文将工程模型设计划分为 2个层次 ,提出了基于实例的定性布置和基于约束的参数布置相结合的布置设计求解模型。     

基于建筑CAD协同设计的权限管理系统

通过对现代集团的企业调研和建筑CAD协同设计系统的特点进行分析,将基于角色的权限管理模式与建筑协同设计相结合,将建筑CAD协同设计中的用户、角色、权限相关联,完成了协同设计系统中权限管理的设计和开发。     

STL实体模型的拓扑重建及其缺陷修复

STL文件是CAD系统与快速成型制造系统之间进行数据交换的标准格式文件，由于CAD系统在生成STL文件时使用的转换方法不当，使得由STL文件描述的实体模型有许多缺陷，要修复缺陷建立实体模型的拓扑关系是必要的。该文首先对STL实体模型进行了拓扑关系重建，然后修复了一些实体模型中常见的缺陷。     

Encapsulation of geometric functions for ship structural CAD using a STEP database as native storage

It is difficult to support collaborative design with a conventional ship CAD system that manages design information using files. The file storage, however, can be replaced with a commercial database management system. This paper describes OpenDIS, which is an interface between the geometric modeling kernel and the DBMS. The main purpose of OpenDIS is to implement a CAD system that has the STEP database as the native storage. A prototype CAD system has been implemented using the OpenCascade geometric modeling kernel and ObjectStore, a commercial object-oriented DBMS. The STEP methodology is used for the database schema. This CAD system has been applied to the hull design process of a ship in order to verify the usefulness of the interface.     

基于Web的车身设计CAD／CAE信息集成系统研究

针对车身开发设计中CAD、CAE子系统间相互独立，导致车身设计效率低的问题，开发了汽车车身设计CAD／CAE信息集成系统，该系统由可视化查询模块、结构化查询模块和数据库模块组成，该系统易于实现对先进设计和管理技术的支持，实现对分布式异构CAD与CAE应用系统支持下的产品进行虚拟设计，达到对内可支持并行工程的虚拟设计，对外可支持异地合作设计的目的。     

基于UG二次开发的卫生陶瓷坐便器产品CAD系统

在分析坐便器等卫生陶瓷产品结构和研发过程的基础上,建立了其产品CAD系统的整体架构和产品设计流程,运用UG/OPEN KF实现了设计参数的集成,采用NURBS曲线和组合曲线作为特征控制曲线构建特征模型,解决了产品多样性、参数化特征相关及模型修改等关键技术问题.以通用CAD软件UG为平台,运用VC 和UG/OPEN进行二次开发,建立了卫生陶瓷坐便器产品的CAD系统.该系统可实现产品的快速设计,对提高产品研发能力有重要意义.     

A CAD-CAE Integrated Injection Molding Design System

. In the injection molding design process, interaction between design and analysis is very intensive. This is to ensure that the plastic part being designed is manufacturable by the injection molding process. However, such interaction is not supported by current computer-aided systems (CAD and CAE), because design and analysis are realized as isolated modules. Although most of CAE systems provide built-in modeling tools, these are only meant for developing an analysis model with very limited CAD functionality. On the other hand, some CAD systems have allowed certain CAE systems to run under their environments, but inherently they use different data models, thus communication between them is poor. This paper presents an innovative, CAD-CAE integrated, injection molding design system. This system uses an integrated data model for both design and analysis. The system is built on top of existing CAD and CAE systems, which not only greatly saves development effort, but also makes full use of the strong functionality of commercial computer aided systems. The system architecture consists of four layers: a CAD and CAE platform layer; a CAD-CAE feature layer; a model layer; and a GUI layer. Two design cases were studied to illustrate the iterative design-analysis process and use of the developed system.     

基于数据库的支持群体工作CAD软件的设计与实现

目前ＣＡＤ系统多是面向单个设计者，而实际的设计工作往往由多个设计者协同完成。ＣＡＤ系统应该支持多个设计者协同工作以提高工作效率。作者采用在现有的ＣＡＤ系统中加入支持设计者协同工作的模块的方法。利用这种方法将ＢＩＣＡＤ中的结构建模模块ＭＯＤＥＬ修改为ＣＷＭＯＤＥＬ，它可支持多个设计者协同工作并能缩短设计周期。实践证明这种方案是可行的。     

Product design logic for an intelligent product modelling system

Recent research in CAD systems has been conducted to realize intelligent processing. Several CAD systems and product modelling systems have been developed using AI techniques. However, in order to develop more intelligent CAD systems, the design logic which connects the functional requirement to the geometric and the technological information of the designed product must be evaluated.

A product model used in such intelligent CAD systems has to include not only the geometric and the technological information of the product but also the designer's thought process which explains the design logic.

Design logic is generally divided into two parts. One is the generalized design logic which is commonly used in the conceptual design of mechanical products. The other is the product specified design logic which is used in the fundamental and detailed design phase. Different logic is applied to each product. This type of design logic is often used in modification design and compilation design, where the dimensions of parts have to be modified according to different functional requirements. When the dimensions and accuracies of the products are defined in connection with the functional requirements through design logic, the CAD system can automatically make decisions according to the given requirements. In this paper, suitable presentation formats and processing functions for these two types of design logic are discussed.

The importance of design logic in product modelling is proven through several case studies in this paper. As a conclusion, the intelligent product modelling system is developed, which should expedite the progress of design automation in the near future. In conceptual design, the design logic is processed in the modelling system and the product structure, with the technological information decided automatically from the functional requirement. Automation in the detailed design phase is also facilitated by the modelling system using the product specified design logic in the product model.     

An architecture for the vertical integration of tooling considerations from design to process planning

To meet the competitive demands of modern manufacturing, it is necessary to reduce design times and enrich decision making by integrating process planning into the design activity using Concurrent Engineering principles. Although this is traditionally done through the interaction between designers and process planners, it is perhaps more desirable for a CAD system to have the functionality necessary to automatically advise the designer of the shop floor implications of design decisions. Cutting tool selection is an essential thread linking feature-based design of machined parts to process planning. Thus, the implementation of tooling considerations into design is an important requirement for an integrated CAD/CAPP system. This paper defines an architecture to enable the vertical integration of tooling considerations from early design to process planning and scheduling. The architecture is based on a five-level tool selection procedure which is mapped to a time-phased aggregate, management and detailed process planning framework. This paper draws on literature and the results of an industrial survey to identify the tooling methods suitable for integration within a CAD system and categorises them into the five levels of tool selection. The functions are then placed on a time-dependent framework that covers the progression of a product from design to process planning. The new functionality is being implemented as an object-oriented application called VITool, which is being developed so that it can be fully integrated within an existing CAD system.