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
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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