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Standards for CAD Data Exchange. The CAD data is of four types Shape Non shape Design Manufacturing data. Process Planning. Product Data Management. CAD data is used throughout the organization. Product Design. Product Design (CAD). Engineering and Analysis (CAE). Marketing.
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The CAD data is of four types • Shape • Non shape • Design • Manufacturing data
Process Planning Product Data Management CAD data is used throughout the organization Product Design Product Design (CAD) Engineering and Analysis (CAE) Marketing Customer Requirements Neutral I/F Product Information Management Product Databases Neutral I/F Supply Management Manufacturing Engineering Suppliers Materials Planning Manufacturing Databases Procurement Customer Installation and Distribution Fabrication, Assembly & Test Operations
Typical Situation Major supplier uses I-DEAS Partner uses Unigraphics Major company uses CATIA Small supplier uses Solid Edge Small supplier uses AutoCAD
The Problem • Every CAD system uses its own proprietary data format • Design data must be converted from one format to the other
Direct Translation between CAD Systems • Need a translator from every CAD package to every other • For 4 CAD packages, need 6 translators • For 6 CAD packages, need 16 translators! I-DEAS Unigraphics CATIA Pro/Engineer
Data Exchange Standards • To address the problem, many standards for CAD data exchange have been developed • CAD systems can import and export to many of these standard formats. • To deal with all CAD systems, you must support I-DEAS, Unigraphics and CATIA ,Pro /E • For small companies, this is very difficult.
A Better Solution • A better solution is development of reliable data exchange standards, using a neutral interface
CAE 1 CAD 1 CAD 2 CAE 2 Neutral Interface CAQ CAPP PP&C CAM Neutral Interface
Requirements of an Interface • The interface must be capable of handling all manufacturing data • There should be no information loss • The system must be efficient to be capable of handling the realtime requirements of manufacturing • The system should be open-ended to permit extensions or contractions
Requirements Continued • The system should be adaptable to other standards • The system must be independent of the computer and architecture used • Test procedures must be provided to verify effectivety.
Evolution of Data Standards Interfaces Standardization Organization CAD/CAD CAD/CAM National & European International ISO IGES PDDI SET VDA/FS CAD*I CIM-OSA EDIF ANSI (USA) PDES Product Data Structure AFNOR (France) STEP DIN (Germany) ESPRIT (EEC) ( A full data model) ESPRIT (EEC) USA Electronics Industry ???
Initial Graphics Exchange Specification (IGES) • IGES defines neutral database in the form of a file format, which describes an IGES model of modeling data of given product • IGES model can be interpreted by dissimilar CAD/CAM systems. • Supports many 2D and 3D CAD entities • Has gone through several versions since 1980 • Widely supported
Data Exchange using IGES Native Database Native Database IGES Preprocessor Post processor Archival data base
File structure and File format • Put IGES • Get IGES Combined in compressed ASCII format
Testing • Reflection Test • Transmission Test • Loopback Test
Problems with IGES • Many incompatible “flavours” • Unreliable translation, particularly for complex geometry • No formal information modelling basis • Insufficient support for conformance testing
PDES • PDES is an exchange for product data in support of industrial automation.
PDES Architecture Mechanical products Electrical Products AEC Products Application N Application Layer Logical Layer Generic entities App. specific entities Physical Layer File format and data structure
Product data exchange using PDES Product data Product data Discipline model Preprocessor Three layer architecture Data exchange unit Postprocessor Discipline model Archival product data