NAFEMS How To Use STEP Geometry for Engineering Analysis

Due to the evolving nature of the engineering analysis and simulation market this publication no longer represents current best practice and has been archived. The document may be of historical interest and is therefore still available for purchase.

This guide is aimed at system managers who are implementing and supporting data exchange by purchasing STEP interfaces and users who want to communicate with customers and/or suppliers about using STEP for data exchange.

What the guide covers:

What STEP interfaces are available
What the parts and conformance classes cover
How to choose which part and conformance class to use.

During the course of engineering analysis there are many information flows which would benefit from the availability of neutral file exchange. The group who have developed this guide are primarily involved in the Computer-Aided Design (CAD) to Finite Element interface. However, the parts of STEP which cover FE data are not yet at International Standard level prototype implementations have been developed. Therefore this guide is restricted to the exchange of engineering data between a CAD system and a FE pre-processor.

1. INTRODUCTION	6
2. HOW TO USE STEP	8
2.1 Commonly Available Interfaces	8
3. OVERVIEW OF STEP	9
3.1 Background	9
3.2 Structure	9
3.2.1 Resource Layer	10
3.2.2 Application Layer	10
3.2.3 Implementation Layer	10
3.3 Standardisation Process	11
4. GEOMETRIC MODEL TYPES	13
4.1 Wire-frame Model	14
4.2 Surface Models	14
4.2.1 Geometrically Bounded Surface Model	14
4.2.2 Surface Models with Topology	15
4.3 Solid Models	15
4.3.1 Boundary Representation (B-rep) Models	15
4.3.1.1 Faceted B-rep Models	16
4.3.2 Constructive Solid Geometry (CSG) Models	17
5. AIC PARTS	18
5.1 Introduction	18
5.2 Geometrically Bounded Surface - part 507	19
5.3 Non Manifold Surface - part 508	19
5.4 Manifold Surface - part 509	20
5.5 Geometrically bounded wireframe - part 510	20
5.6 Topologically bounded surface - part 511	20
5.7 Faceted B-rep - part 512	20
5.8 Elementary B-rep part 513	21
5.9 Advanced B-rep part 514	21
5.10 Constructive solid geometry - part 515	21
6. STEP APPLICATION PROTOCOLS AND CONFORMANCE CLASSES	22
6.1 AP 203 Configuration Controlled Design	22
6.1.1 Scope	22
6.1.2 Information Requirements	24
6.1.3 Conformance Classes of AP203	25
6.2 AP214, Core Data for Automotive Mechanical Design Process	27
7. GEOMETRY EXCHANGE PROBLEMS	29
7.1 Different Representations	29
7.1.1 Entity conversions	29
7.1.2 Approximation Problems	29
7.2 Geometric Precision Problems	30
7.2.1 Geometric Tolerance	31
7.2.2 Geometric Healing	32
8. FUTURE DEVELOPMENTS	33
8.1 SDAI	33
8.2 AP209	33
8.3 Modular Application Protocols	35
8.3.1 Application Modules	36
8.3.2 Modular AP	36
8.3.3 Engineering Analysis Core Model	37
8.4 Benefits of Modularisation	37
A. RESOURCE PARTS OF STEP	38
A.1 Part 41	38
A.1.1 Product Definition	38
A.1.2 Product Property Definition	38
A.1.3 Product property representation	39
A.1.4 Measure	39
A.2 Part 42	39
A.2.1 Geometry Schema	39
A.2.2 Topology	41
A.2.3 Geometric model schema	41
A.3 Part 43	43
A.4 Part 45	43
B. GLOSSARY	45
C. FURTHER INFORMATION	50
C.1 Books, Reports and Newsletters	50
C.2 WEB Sites	50

Document Details

Reference	HT12
Authors	Goult. R Greenfield. D
Language	English
Audience	Analyst
Type	Publication
Date	1st January 2001
Region	Global

Download

E-Library Download

Purchase Download

Order Ref	HT12 Download
Member Price	£5.00 \| $6.33 \| €6.05
Non-member Price	£15.00 \| $18.97 \| €18.13

Back to Previous Page

How To Use STEP Geometry for Engineering Analysis

Contents

Document Details

Download

Purchase Download

NAFEMS Membership