STEP MANAGEMENT OVERVIEW

STEP ARCHITECTURE

Module 4Estimated Viewing Time: 60 Minutes

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The NationalThe National Institute of Standards & TechnologyInstitute of Standards & Technology

Developed Under Contract by:

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Topics for This Module

Data Architecture STEP’s underlying semantic “backbone”

Representation Forms The EXPRESS Modeling Language

Document Architecture The structure of the STEP Standards documents

Application Protocols An introduction the implementable portion of STEP

Design Principles behind STEP

Incorporate meaning of data into a data structure

Provide a formal and computer sensible data modeling language

Utilize a development process that allows subject area experts to focus on the meaning of the data to be exchanged

Retain independence of data (enterprise information) from implementation types (a single representation (or model) can be used across all types)

Data Architecture: Shareable and Extensible

The conceptual data models represent a consensus view of the data semantics commonly used in product data subject areas and understood by a category of application systems

The reuse of general ideas within different contexts is supported by levels of semantic abstraction (encapsulation)

The models are integrated into a single, conceptual schema using a consistent data architecture

The semantics are partitioned to permit extension and pruning (modular design)

Aircraft: B-2 Bomber, engine, radar system

B-2 Bomber prototype design 1

As-Design definition, As-Maintained definition, Functional-design definition

Shape, material property, design requirement, functional characteristics

Geometric model, chemical composition, textual description, measurements, numbers`

Product

Formation(version)

Life cycledefinition

Properties

Representation

STEP Data ArchitectureSimple Example

shape

dimensional representation, geometric representation

Properties

Representation

Geometry

length=3 mmwidth=4.5 mm

high-performanceaerodynamic shape

reference to a document

Parametric

Descriptive

Raster Image

boundary rep, constructive solid geometry

planar surfaces,free form surfaces

curves and points

SolidSurfaceWireframe

STEP Data ArchitecturePopulation Example

Printed_circuit_assembly

building_element

piping_component

part_librarydefinition

manufacturing_planning definition

functional_designdefinition

Product

Formation(version)

Life_cycledefinition

STEP Data ArchitectureSemantic Extensions Examples

Semantic Extensions Examples

STEP DATA ArchitectureProduct

Formation(version)

Life cycle definition

SurfaceWireframe Solid

Geometry

Properties

Shape

Material

Surface Finish

Structural

Behavioral

Representation

Raster Image

Descriptive

Parametric

Examples of capabilities for the description of Properties and Representation

EXPRESS

Declarative object-like, Pascal-like, information modeling language

Used to specify data semantics and structure for Data Architecture and other STEP specifications

Entities, Types, Rules and Functions are basic constructs of EXPRESS

Logical collections of data constructs are partitioned into Schemas

Formal syntax permits automated processing of EXPRESS models

The EXPRESS Language

SET [1:?] subcategories

of product

of productproduct_version

version

product_definition_relationship

first_related_definition

second_related_definition

product_definitionfirst_equivalentsecond_equivalent

product_definition_equivalence

product

product_category

Graphical Representation

SCHEMA product_definition;

TYPE identifier = STRING;END_TYPE;

TYPE label = STRING;END_TYPE;

ENTITY product_category; name : label; subcategories : OPTIONAL SET [1:?] OF product_category; of_product : product;END_ENTITY;

ENTITY product_version; ident : identifier; name : label; description : OPTIONAL text; of_product : product;END_ENTITY;

Textual Representation

STEPDocument Architecture

Application Protocolsand Abstract Test Suites

Parts 200+ & 300+

Generic Resources Parts 41-99

Application Interpreted ConstructsParts 500+

Integrated Resources

Application Resources Parts 101+

Implementation MethodsPart 21 Physical File,

Parts 22-29 Data access method

Description Methods

Part 11 EXPRESS

Framework

Part 13 STEP Development Methodology

ConformanceMethods

Part 31 Conformance Testing Methods: General Concepts

Parts 32-35 Reqs for Test Labs & Clients Test Methods for File & Data access method

Integrated Resource Parts

General purpose product data specifications written in EXPRESS

Provide the "building blocks" or "vocabulary" for Application Protocols

Two classes: General Resources (40 series) Application Resources (100 series)

Development of the Integrated Resources

Generic Resources

ShapeRepresentation

StructureGeometric Models

Presentation

Product Description Fundamentals

Application ResourcesFinite

ElementAnalysis

Draughting

Application Protocols

An Application Protocol defines the usage of STEP Product Data for a given application context.

An Application Protocol represents a measurable and shareable subset of STEP capability that is expressed in an industry’s or discipline’s terminology.

Generic Resources

ShapeRepresentationStructure

Geometric ModelsPresentation

Product Description Fundamentals

Application Resources

FiniteElementAnalysis

Draughting

Application Protocol Concept

ApplicationProtocol

Requirements

RequiredSTEP Resources

Mapping

Generic Resources

ShapeRepresentationStructure

Geometric ModelsPresentation

Product Description Fundamentals

Application Resources

FiniteElementAnalysis

Draughting

ApplicationProtocol #1

Requirements

ApplicationProtocol #2

Requirements

Mappings

CommonResources

Application Protocols ShareCommon Resources

Application Protocols: Re-use and Specialize Common

Constraints -- Example

Assy_Structure(Network Structure)

Assembly Schematic

Schem_Diagram(Network Structure)

Piping

Piping_Run(Network Structure)

Network Structure

Shape Product Identifier

Material

Specification

Version

Integrated Resources

Elements of an Application Protocol

Application Activity Model A function model that describes the activities and processes of

defined application context domain. This is a requirement document.

Application Reference Model An information model that describes the information requirements

and constraints for an application context area. The model uses application-specific terminology and rules that are familiar to experts in the application area.

Application Interpreted Model An information model that describes the STEP data structures

required for functional equivalence with the application contexts' AAM's and ARM's.

Conformance Classes Descriptions of the valid populations of the file, which serve to

define conformant uses of the AP.

AIM

ARM

AAM

AP TestPurposes

STEP Exchange Format Part 21: Clear text encoding of the exchange structure

Is the algorithm used in the exchange of data via a physical file format.

Result is a sequential file of ASCII characters described in a computer-interpretable form.

Defines the mapping from EXPRESS into the exchange file:

ENTITY product_category; name : label; subcategories : OPTIONAL SET [1:?] OF product_category; of_product : OPTIONAL product;END_ENTITY;

ENTITY product_version; ident : identifier; name : label; description : OPTIONAL text; of_product : product;END_ENTITY;

#1=product_category(“process vessel”,(#2),$)#2=product_category(“tank”,$,#3)#3=product(“fuel storage tank, 55 gals”)#4=product_version(“ver-001”,”Original Design”,$,#3)

Standard Data Access Interface - SDAI

Specifies a standard access mechanism to data- bases that can be specified in EXPRESS

Permits application system independence from data storage technologies

Has an object-oriented view of data, regardless of implementation

Implementations in a particular programming language require an interface language

STEP Conformance Testing

Conformance Test Case(hardcopy)

Validate IGES or Part 21 files

Why tje product support mail and this is a bunch of nonsense but we

JIEO-E-2300 Checklist

have to type in something to make it look like it says something.

Does tje product support mail?

Will this product really be produced?

Do you plan on providing support?

Will you promis that you will be good to your users?

Can you send your forms over an EDI transaction?

When will this all be over?

I'm getting tired of this aren't you?

Well just a few more thoughts to make it look goof.

Will your product really wrok as advertised?

Will you sell this product for less than $9.95 and if not why not.The last time I want to have to do this..

Do you support database access using standard DBMS?The last time I want to have to do this..

Verdict CriteriaConformance Test Case

(IGES or Part 21 files)

Certification Validate Hardcopy

Implementation Under test

STEP ARCHITECTURE

End of Module 4