ISO BULLETIN JANUARY 2002 9

ISO 10303 – STEP A key standard

for the global market

SPOTLIGHT

By Howard Mason, Chair, ISO/TC 184, Industrialautomation systems and integration,

SC4, Industrial data

The growth of electronic commerce for simplebuying and selling over the Web is well documented, but it represents only part of thepotential impact of electronic business. Thisarticle explores an area of electronic businesswhich is far more challenging and has thepotential to bring much greater reward to the global economy. As manufacturing andconstruction industries become more global,there is a growing demand to exchange thedigital definition of products themselvesbetween different organizations as the product moves from design through manu-facture to long-term support.

ISO 10303, STEP – the STandard for theExchange of Product model data – is a comprehensive series of documents which provides industry with a major capability toexchange and share the information used todefine a product, throughout the supply chainto the end customer and throughout the entirelife cycle of the product. It is already in use toshare simple CAD (Computer Aided Design)information, product models, complete product structures and technical drawings, aswell as the underlying analysis informationin industries such as aerospace, automotive,shipbuilding and construction.

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The business contextfor STEP

around the world. The product may be inservice for 30 years or more, and the cus-tomer demands accurate information ondelivery and throughout the life cycle.

In order to meet the challenge, industryhas increasingly employed computer sys-tems to develop digital definitions of theproduct, offering improved accuracy andquality, greater speed, reduced costs ofrework and the ability to perform addi-

As a consequence, product data needs tobe accessible to a wide range of differentcomputer systems.

Barriers to communication can easilyarise because different computer systemshold data in different forms, and even thesame system can be used in different waysby different individuals. In addition, thelength of the life cycle of many of theindustrial products spans multiple genera-

Today’s global enterprises are seeking todeliver such products to market more rap-idly, with a higher degree of quality andreliability, and higher levels of customerand product support in order to enhancecustomer satisfaction. The global natureof business and its markets demands theability to rapidly create alliances of enter-prises to deliver a particular product,whilst seeking to drive down the cost ofproduction and support.

For example, big aerospace projectstoday typically involve a number of majorinternational partners, with up to 10 000suppliers and hundreds of customers

tional analyses of the model before mov-ing to production. Such systems have alsopermitted the development of new busi-ness processes such as concurrent engi-neering.

One of the results of this trend is thatthe digital data is becoming the soledesign authority for the product, andproduct data held in digital form repre-sents a major investment for the manu-facturing industry. Digital product datacan be used where and when it is neededthroughout the extended enterprise andthroughout the life cycle of the product. Itcan also be delivered to the end customer.

tions of hardware and software technology,so there is a major requirement to readlegacy information from new systems.

Re-creation or duplication of productdata between systems leads to inconsisten-cies and does not add value, so there is alarge and growing demand for accurateand unambiguous translation of productinformation between different systems.The business need for more partnershipsand more flexible subcontracting, as wellas internal business improvement pro-grammes, further reinforce this demand.

One solution would be simply todevelop interfaces between systems as

STEP (ISO 10303) is already in use to share simple CAD information, product models, complete product structures and technical drawings, as well as the underlying analysis information in industries such as aerospace, automotive

(above), shipbuilding and construction. Current development activities include suites of application protocols to support the shipbuilding and furniture industries and the construction of process plants such as oil refineries.

Major industrial products such as aircraft,ships, buildings and industrial plantshave a lifetime measured in decades, orlonger. These products are becomingmore and more complex as they deliverincreased functionality, with embeddedsoftware systems.

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required, but this rapidly produces a largenumber of translators which are expen-sive to maintain. Four systems require 12interfaces - for 10 systems, this numbergrows to 90 and the problem rapidly spi-rals out of control, since a change in onesystem may require changes to be madeand tested to all the interfaces to the sys-tem.

The role of the STEP standard (ISO10303) is to provide that data backbonefor product information. The standarddefines an integrated information modelwhich supports multiple views of productdata for different applications. The inte-grated model is documented in the STEPIntegrated resources (currently Parts 41-50) and Application resources (currentlyParts 101-108), which are extended asnecessary to support additional informa-tion requirements as they are discovered.

For each application area covered bythe standard, a standardized Applicationprotocol (Parts 201-238) is defined whichdescribes the scope of the informationrequired by the application in terms that

are familiar to application users. The useof the information may be illustrated by asupporting activity model, which showsthe processes that the Application protocolcan support. The Application protocolthen defines the mapping between theusers' view of the information and theintegrated STEP information model. Theresulting standardized definition of infor-mation can be used to develop and vali-date translation software for differentcomputer systems serving that area ofapplication. For some application proto-cols, the market has supported the devel-opment of standardized testing informa-tion, which may be applied for confor-mance testing of different implementa-tions of the standard (parts 31-35 and the300-series).

The STEParchitecture

A more cost-effective solution is to linkeach system to a common data “ back-bone ”, which requires each system tohave only two interfaces, translatinginformation between the native formatand the neutral form of the backbone, andisolates changes to those interfaces.

Concept

Design

Manufacture

Assembly

Testing

Delivery

Support

The role of the STEP standard (ISO 10303) is to provide a data“backbone” for product information.The standard defines an integratedinformation model which supportsmultiple views of product data for different applications.

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This approach is designed to provideinteroperability between different applica-tion views of the integrated model, and isfurther enhanced by the standardizationof collections of data which are commonto multiple application protocols. Theadditional standardization of Applicationinterpreted constructs (as parts 501-520)and Application modules (Parts 1001upwards) facilitates implementation oftranslators and reuse of software. Forexample, the PDM schema provides acommon information model to supportproduct assembly structures and bills ofmaterial for multiple applications.

their complex plumbing into an air-liner, replacing expensive physicalmockups;

the use of the PDM schema to com-municate design and build assemblystructures between the four nationalpartners of the Eurofighter project;

the AIRBUS use of STEP standards forCAD-PDM exchange for the A380 pro-gramme, and its intent to use themmore intensively in the near future;

the use of the STEP Draughting appli-cation protocol for the exchange oftechnical drawings between Japanesecompanies and the Ministry ofConstruction.

A number of nations have set up theirown STEP Centres to support industrialexploitation of the technology. TheseCentres regularly cooperate to advanceprogress and promote successes in imple-mentation of the standard. Their Web sitescontain many more examples of successfulSTEP implementation – see http://isc.aticorp.org

All STEP information models aredefined using the EXPRESS data defini-tion language (Part 11) which was devel-oped at the start of the project in the mid-1980s to provide the necessary informa-tion modelling constructs to support thecomplex relationships of product infor-mation. The use of the EXPRESS lan-guage is supported by a range of softwaretools which can assist the process of mod-elling and developing translators.

The information in EXPRESS datamodels can be represented in a simplephysical file form as a text string (part21), or mapped into any other form ofrepresentation. It is completely independ-ent of the representation format.

First published in 1994, the initial scope ofSTEP covered geometry, product structureand technical drawings. Since that date, thestandard has been extensively implementedon major industrial projects in the aero-space, automotive and other industries.

Typical implementations use STEP tocombine the information on the shape andother characteristics of individual partswith assembly structures to form a singleintegrated representation of a complexassembly or product. This information isgathered from a range of application sys-tems and consolidated into a STEP filewhich can be transferred to other compa-nies and unloaded into their correspondingsystems. The advantage from combiningthis data is that it guarantees consistencyfor information deliveries, and avoids theadministrative cost of ensuring that data isconsistent between multiple systems.

Landmark examples include:

the use of STEP to support theexchange of digital mock-ups betweenBoeing and its engine suppliers in theprocess of integrating engines and TC 184/SC 4 has recently completed a

major extension to STEP which offers abroad range of new functionality. Thecapabilities in the initial release havebeen extended to cover geometry forprocess planning of manufactured com-ponents, sheet metal dies, finite elementanalysis, design and manufacture ofprinted circuit assemblies, electricalwiring harnesses and integrated electro-mechanical systems. Other extensionsinclude building, construction andprocess plant information.

These new capabilities build on theestablished core model of STEP, which hasbeen extended to support the additionalinformation requirements.

As new IT capabilities for informationexchange have emerged, TC 184/SC 4 hasalso standardized database access inter-faces, language bindings and mostrecently, a mapping to XML (part 28), all

“Re-creation or duplication of productdata between systemsleads to inconsistenciesand does not addvalue”

Typical implementations use STEP to combine the information on

the shape and other characteristics of individual parts with assembly

structures to form a single integratedrepresentation of a complex

assembly or product.

An extensively imple-mented standard inaerospace, automotiveand other industries

The latestrelease

(Continued after the special insert)

ISO BULLETIN APRIL 2002 13

of which use the common EXPRESS datamodels. An XML schema mapping is underdevelopment, and the use of the EXPRESSlanguage guarantees that the STEP datamodels can be supported by further inno-vations in information technology as theyrapidly evolve. This provision for extensi-bility is essential to protect the investmentof industry in its information.

other computer-interpretable representa-tions which can be directly implemented.This approach eliminates non-value-addedtranscription and duplication of informa-tion.

TC 184/SC 4 is also planning to extendSTEP to support the information require-ments of Systems Engineering, materialproperties and a more integrated approachto process planning for manufacture. Incooperation with TC 184/SC 1, it is devel-oping STEP-NC, which will allow fullydetailed STEP models and the associatedprocess planning information to be deliv-ered directly to new-generation numeri-cally-controlled machine tools for auto-mated manufacture, eliminating the needfor manual process planning. These newcapabilities directly exploit the results ofmajor research and development activitiesin Europe and the USA.

STEP is a proven standard for theexchange and sharing of digital productinformation throughout the product lifecycle. It is based on sound principles ofinformation modelling, and is continu-ally expanding to cover new areas of func-tionality and new information exchangetechnologies. It provides organizationswith the capability to exchange informa-tion between different computer-aideddesign, manufacturing and support sys-tems independent of the industry sector.

STEP technologies are already beingexploited by other ISO technical committeeswhich have the need to exchange digitalproduct information. Good examples areprovided by TC 29, Small tools, on the defi-nition of cutting tools and TC 172, Opticsand optical instruments, on optical equip-ment. STEP technology is available forother groups to use to support their need forexchange of technical drawings and otherproduct information, and it provides an easyroute for migrating traditional ISO productstandards into the information age.

The current development activitiesinclude suites of application protocols tosupport the shipbuilding and furnitureindustries and the construction of processplants such as oil refineries.

About the authorHoward Mason

The author works for BAE SYSTEMS inthe United Kingdom, and is responsi-ble for Engineering and InternationalStandards in the Grouo InformationSystems organization. He has beeninvolved in industrial automationstandards for ISO/TC 184/SC 4 and itsparent YTC since they were launched,and became Chairman of SC 4 inAugust 2000. Howard Mason alsochairs the European mirror commit-tee to ISO/TC 184, CEN/TC 310, andthe industrial consortium developingthe PLCS extension to STEP. He is anactive member of the ManagementGroup of the Memorandum ofUnderstanding on e-Business betweenISO, IEC, ITU and UN/CEFACT, and afounder member of the Board ofBSI/DISC.

Future developments in industries from ship-building to furniture

The extension of the STEP standard tosupport the information required for lifecycle support of products demonstrates aninnovative approach to standardization.Having agreed the requirements within theISO community, the PLCS consortium wasput together with industry, governmentsand vendor partners to rapidly develop andtest the necessary standards in a realisticenvironment prior to standardization. Thisapproach brings together the most effec-tive elements of the ISO consensus processand the speed of development offered byconsortia, resulting in rapid developmentof an international standard. The firstmajor demonstration of PLCS took placein September 2001, showing how fieldmaintenance reports could be fed back tothe manufacturer, problems assessed,design changes evaluated and modifica-tions deployed throughout the fleet.

A further innovation comes from the useof the XML language to develop the compo-nents of standards so that scripting toolscan be used to generate from a commonsource the formal ISO documentation and

“A further innovationcomes from the use of the XML languageto develop the compo-nents of standards.”

A proven standard, basedon sound principles ofinformation modelling

Please contact the Chair or theSecretariat for additional information, or see our new Web site at www.tc184-sc4.org.

The use of STEP to support theexchange of digital mock-ups betweenBoeing and its engine suppliers in theprocess of integrating engines and theircomplex plumbing into an airlinerreplaces expensive physical mockups.