The document discusses standards for exchanging CAD data between different CAD systems. It notes that there are four main types of CAD data and that each CAD system uses its own proprietary format. Directly translating between each system's format would require many translators. Instead, neutral data exchange standards like IGES and PDES have been developed to allow CAD data to be imported and exported between different systems without information loss. The standards aim to support all types of manufacturing data and requirements in an open and adaptable manner.

1. Standards for CAD Data Exchange

2. • The CAD data is of four types
• Shape
• Non shape
• Design
• Manufacturing data

3. Product
Design
(CAD)
Engineering
and Analysis
(CAE)
Customer
Requirements
Product
Databases
Manufacturing
Databases
Materials
Planning Procurement
Installation
and
Distribution
Fabrication, Assembly & Test Operations
Product
Information
Management
Product Design
Manufacturing
Engineering
Supply Management
Customer
Suppliers
Marketing
Process
Planning
Neutral I/F
Neutral I/F
Product Data Management
CAD data is used throughout
the organization

4. Typical Situation
Major company
uses CATIA
Major supplier
uses I-DEAS
Small supplier
uses AutoCAD
Small supplier
uses Solid Edge
Partner uses
Unigraphics

5. The Problem
• Every CAD system uses its own proprietary
data format
• Design data must be converted from one
format to the other

6. 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
Pro/Engineer
CATIA

7. 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.

8. A Better Solution
• A better solution is development of reliable
data exchange standards, using a neutral
interface

9. CAD 1 CAD 2 CAE 1 CAE 2
Neutral Interface
CAPP PP&C CAM CAQ
Neutral Interface

10. 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

11. 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.

12. Interfaces
CAD/CAD CAD/CAM
Standardization Organization
National & European International ISO
IGES
PDDI
SET
VDA/FS
CAD*I
CIM-OSA
EDIF
PDES ANSI (USA)
AFNOR (France)
DIN (Germany)
ESPRIT (EEC)
ESPRIT (EEC)
Product Data Structure
STEP
( A full data model)
USA Electronics Industry ???
Evolution of Data Standards

13. 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

14. Data Exchange using IGES
Native
Database
Preprocessor IGES
Archival
data
base
Post processor Native
Database

15. Combined
in
compressed
ASCII
format
File structure and File format
• Put IGES
• Get IGES
Flag section(Optional)
Start section
Global Section
Directory Entry section
Parameters Data section
Terminate section

16. Testing
• Reflection Test
• Transmission Test
• Loopback Test

17. Problems with IGES
• Many incompatible “flavours”
• Unreliable translation, particularly for complex
geometry
• No formal information modelling basis
• Insufficient support for conformance testing

18. PDES
• PDES is an exchange for product data in
support of industrial automation.

19. PDES Architecture
Mechanical
products
Electrical
Products
AEC
Products
Application
N
Applicati
on Layer
Generic
entities
App. specific
entities
Logical
Layer
File format
and data
structure
Physical
Layer

20. Product data exchange using PDES
Archival
product
data
Three layer
architecture
Data exchange
unit
Preprocessor
Discipli
ne
model
Product
data
Post processor
Product
data
Discipline
model