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The buildingSMART Glossary of Terms

International Alliance for Interoperability

Model Support Group

January 2007


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Glossary of Terms 2 of 33

The scope of this document is to provide guidance on the meaning of terms used inassociation with the Industry Foundation Classes (IFC) model and related activities.

This document is not intended to be a general glossary of terms for Information andCommunications Technology

All rights reserved. No part of the contents of this document may be

reproduced or transmitted in any form or by any means without the written

permission of the copyright holder (IAI).

Copyright 1996-2007 - International Alliance of Interoperability (IAI)

Document Control

Project Reference MSG Glossary

Document Reference The buildingSMART Glossary of Terms

Version 0.5

Date 2nd January 2007

Status DRAFT

Primary Editors Jeffrey Wix, Kari Karstila

IAI Committee Responsible Model Support Group

Distribution MSG

Version 1.0 02/01/2007 - Public release of The buildingSMART Glossary of Terms.


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Introduction

The purpose of this glossary is to define a list of the terms used when talking about

information and communication technology in construction and facilities

management. Special emphasis is on the terms related to the buildingSMART idea

including those dealing with information modeling, data exchange, IFC and related

activities.

Many sources have been consulted in compiling this Glossary. Significant amongst

these are the glossaries published by the ProIT project in Finland, the Avanti

programme in the United Kingdom and the EU funded ICCI project. However, a

number of other sources were used and those that are of primary interest are listed in

the References section.Some of the terms in the glossary are better known by their abbreviated form (or

acronym). For such terms, the Abbreviation is provided is a separate column in

addition to the meaning.

Terms given in the glossary may be related to other terms. This may be either because

the related term adds to the definition or because there is some other linkage. Where

relationships exist, these are given in the Related column.


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Glossary

Abbreviation Term Definition

4D 4D 4D = 3D + time, i.e. the linking of time aspect to the building element and space objecmodel. The time aspect may describe e.g. the installation date and time of building ele

simulation can be used to visualize the progress of construction in time.

5D 5D 5D = 3D + time + cost i.e. the linking of both time and cost aspects to the building eleobjects of the 3D-model. The 5D aspect may be used to describe the occurrence of co

particular times during the development of a project and may be used to visualize the

income return, life cycle cost or other developing cost pattern for a project.

Abstract Entity Type An entity type that cannot be instantiated; only non-abstract subtypes of an abstract eninstantiated.

Activity A piece of work to accomplish a result. Describes a generalized piece of doing that is time. This is distinct from a task that typically has a time context.

Activity Model A model that describes an application in terms of the sequence of its activities and inf

Actor A person, an organization or an organizational unit (such as a department, team etc.) iproject during its life cycle.

AEC Architecture, Engineeringand Construction

A phrase that may be used as an alternative to describe the building construction indu

US and related practice.

AEC / FM Architecture, Engineeringand Construction /Facilities Management.

A phrase that may be used as an alternative to describe the building construction indu

subsequent building operations. Prevalent in US and related practice.

AECO Architecture,Engineering,Construction and

Operation

An alternative usage to AEC/FM. More recent definition.


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Aggregate A collection of elements. In the EXPRESS language the types of aggregates are array

Aggregation A special form of association, between a whole and its parts, in which the whole is coparts.

In IFC, aggregation is a subtype of composition in which the composite element may

elements of different entity types.

Application An information system specific to the satisfaction of a set of user requirements.

API Application Programming

Interface

An interface definition that permits invoking services from application programs with

details of their internal implementation.

AIC Application InterpretedConstruct

Specifies the interpretation of the STEP integrated resources to satisfy requirements fo

defined functional area.

AIM Application InterpretedModel

The process, mechanism, or manner by which meaning is assigned to an abstract repre

event, object, or concept. Within an Application Interpreted Model or AIM, the abstra

is specified by an EXPRESS construct. Interpretation results in the creation of a new c

AIM that may restrict, narrow, or constrain the semantic scope of an original construc

specializing it.

AM Application Module Common building blocks used to create modular Application Protocols (AP) within Slevel modules are built up from lower-level modules.

AP Application Protocol A mechanism of the STEP standard for defining well-defined subsets of the total resoSTEP to be used in conceptual models supporting the data transfer needs of particular

areas.

ARM Application ReferenceModel

A conceptual model in STEP that describes the information requirements and constrai

application context.

Architecture Description of the basic arrangement and connectivity of parts of a system.


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Array A type of EXPRESS aggregate that is fixed by size and the elements of which are ind

ASCII American Standard Codefor InformationInterchange

A standard code for representing English characters as numbers, with each letter assig

from 0 to 127.

As-Is Process A process as it is currently.

Attribute In general, attributes represent the characteristics of objects.

E.g. Attributes defined by a building element class may be Name, Length, Weight, Pr

attribute values of a specific building element of a specific building may be Name = 'W

Length=6500.0, Weight=7300, etc.

In EXPRESS, an attribute of an entity type has a name and data type, and they represe

of an entity type and relationships between entity types.

Attribute Value Attributes defined by an entity type get their specific values in the instances of the ent

Backward Compatibility See Downward Compatibility

Bag A type of EXPRESS aggregate that can vary in size, the elements are not indexed by oelements are not required to be unique.

BIM Building InformationModel.

A shared digital representation of physical and functional characteristics of a facility f

standards for interoperability.

A shared knowledge resource for information about a facility forming a reliable basis

during its life-cycle from inception onward.

A basic premise is collaboration by different stakeholders at different phases of the lif

facility to insert, extract, update or modify information in the process to support and r

that stakeholder.Boundary Representation A modeling strategy where objects are modeled using their boundary description.

Bounding Box A minimum bounding volume in the form of a rectangular box such that it completelyobject.


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Code Checking View A view of the IFC Object Model that is designed to support the exchange of informaticonformance with local building codes/regulations.

Compatibility In general, capability of systems' interfaces to work with each other.

Note: With regard to data exchange files, there may be upward compatibility and dow

compatibility.

Complex Instance An instance that is an instantiation of a number of entity types at the same time. A comcollects together component instances from multiple classes into a single instance.

Note: Complex instance is not the same as a composition.

Note: Especially EXPRESS related concept.

Composition In general, a relationship between a composite object and its parts.

In IFC, a type of composition where the composite element can be a composition of e

varying types. The generic composition relationship in IFC is further subtyped into ag

nesting.

Note: Some times also called whole-part relationship.

CFD Computational FluidDynamics

The science of determining a numerical solution to the governing equations of fluid fl

advancing the solution through space or time to obtain a numerical description of the

field of interest

CAD Computer Aided Design A class of software application that performs a design function.

CADD Computer Aided Designand Draughting

A computer aided design software application with additional features such as annotat

enable the production of drawings as output.

CAFM Computer Aided FacilitiesManagement

A class of software application that assists with the planning, execution and recording

management operations.

CAMM Computer Aided

MaintenanceManagement

A class of software application that assists with the planning, execution and recording

maintenance management operations.


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CASE Computer Aided SystemEngineering

Computer Aided System Engineering. (CASE) tools are more or less complete sets of

the process of making software. They typically support the creation of graphical schem

dictionaries (repositories) of all entity classes, their attributes and relations and at last a chosen language.

Computer InterpretableData

Representation of data in a form that can be directly interpreted by computer applicati

human intervention.

Concept Human perception of objects of reality.

Conceptual Model A formal definition of a bounded set of facts, concepts or instructions and relationshipspecified requirement.

Synonym of information model

Conformance In the context of standards, means that the implementation of the standard (e.g. applicexchange interface) is done according to the definitions of the standard.

Consistency A characteristic of a data set that the values that are dependent or derived from each ovalues violating these dependency rules.

Constraint In EXPRESS or data modeling, defines restrictions to the allowable value space of insattribute values.

A limiting value or boundary condition that may be applied to the value of a property

Constructed Data Types Constructed data types of EXPRESS are enumeration and select data types.

Construction Type Defines the decomposition structure of a building element and properties of the buildiType information defines some properties of building elements that may be shared by

elements.

E.g. The construction type of a wall defines the material layers of its cross section.

CSG Constructive SolidGeometry

A geometric modeling methodology where an object is built using the boolean operato

subtraction and difference.

Converter A computer application that converts data from one form to another.


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Coordination View A basic view of the IFC Object Model designed to exchange primarily shape data abospaces and building elements

Data Representation of information in a formal manner suitable for communication, interprprocessing by human beings or computer applications.

Recorded, ordered symbols that carry information.

Database A group of related data sets comprising data that is independent of applications, involrelationships, and is protected by data security

Data Access Interface A programming interface that allows for access to data such that the using applicationfrom how the data actually is stored and managed.

DDL Data Definition Language A formal method for the definition of concepts and their data structures.

Data Exchange The exchange of data between computer applications; typically using a data exchange

Data Exchange File A file of data in data exchange format that is exported by the sending application for ttransferring and importing the file into the receiving application.

Data Exchange Format A computer interpretable format used for storing, accessing, transferring, and archivin

Data Model An abstraction of the real world which incorporates only those properties thought to bapplication at hand. The data model would normally define specific groups of entities

attributes and the relationships between these entities.

Usually used as a synonym for the terms conceptual or information model.

Note: Sometimes a distinction is made between the implementation technology indepe

model, and the data model which is planned for a specific implementation technology

structures of a database).

Note: An Information model for Product data is called a Product data model.

Data Quality Indications of the degree to which data satisfies stated or implied needs.

This may include information about lineage, completeness, currency, logical consisten

of the data


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Data Sharing Common access to data in a database by a number of applications that create, use and

Data Type The definition of the domain of values of an attribute.

Database An organized and managed set of data that one or more applications can use and upda

Datum A point that defines an origin and orientation of a coordinate system.

Decomposition In general, a relationship between parts of a composite object and the composite objecinverse to composition

De-Facto Standard A method or similar which has achieved a position of being the "standard" practice, wstandardized by an official standardization body.

Defined Type In EXPRESS, defined type is a named type that can be by underlying data type be a sidefined types or a Constructed data type.

Definition A concise explanation of meaning of an item of interest.

Derived Attribute An attribute the value of which can be derived from the values of other attributes of thderivation rule can also be seen as a consistency rule between the attribute values.

DTM Digital Terrain Model A method of transforming elevation data into a contoured surface of a three-dimensio

Document A collection of document data that is managed as a single unit.

Document Data Document data gives a textual or graphical description (presentation) of the thing, succan interpret information about the thing.

For example, a person who understands the notations of construction drawings can int

for the building. However, even if the drawing would be e.g. in digital DXF-format, a

application could automatically interpret the meaning of the graphics (lines, circles, te

drawing.

DTD Document TypeDefinition.

A definition of information content using the XML language.


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Event The cause of a state change of an object.

Exchange Format A structure and syntax for encoding data for the purpose of its exchange.

ER Exchange Requirement The set of information that needs to be exchanged to support a particular business reqparticular project stage (or stages).

The purpose of an exchange requirement is to describe the information that must be p

business process to enable another business process to happen.

Explicit Attribute An attribute of an entity type that is not a derived or inverse attribute.

EXPRESS A data definition language defined by ISO 10303-11 EXPRESS language reference mis a formal language that can be used to define product data models.

Note: IFC Object Model is defined using the EXPRESS language.

EXPRESS Model An information model described using the EXPRESS language. An EXPRESS model

number of interrelated schemas.

EXPRESS-G A graphical notation for the EXPRESS language. EXPRESS-G defines graphical symof the elements of the EXPRESS language.

EXPRESS-X A mapping specification language for defining a mapping between data sets based on EXPRESS-models.

EXPRESS-X is defined by ISO 10303-14 within the EXPRESS language family.

Extension In the step-wise development approach of the IFC, an extension extends the IFC Objea new domain. An extension is defined by IFC model development projects.

Facility A physical structure or installation including related site works, serving one or more m

Feature A region of interest on the surface of a part. Features may form a hierarchy with, on thpattern features. Pattern Features may be placed in a hierarchy of sub-patterns, but end

features. Compound features may also be placed in a hierarchy of sub-compound featu

with so-called primitive features. The latter type of features cannot be decomposed fu

File Based DataExchange

Data exchange that happens using files between the sending application and the receiv


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Formal Described in an unambiguous, systematic way.

Format A structure and syntax in which data is encoded.

Full Model Exchange A form of data exchange where the whole product model is exported into an exchange

Note: See also Partial model exchange.

Function In general, the behavior of a thing.

FP Functional Part A unit of information within an exchange requirement that may be fully described andown right.

Generalization In information modeling, creation of a more generic class that captures the common cthe more specific classes.

Creation of a supertype for a number of entity types (subtypes) such that the supertyp

common attributes and constraints of the subtypes, which then do not need to be defin

the subtypes because they are inherited from the supertype.

GML Geographic MarkupLanguage

XML-based language for describing and encoding geospatial information. An applica

specification developed by members of the Open GIS Consortium.

Global Rule An EXPRESS constraint defined outside of entity types, and which may define constrto a number of entity types and their instances.

GUID Globally Unique Identifier A pseudo-random number used in software and database applications. While each gennot guaranteed to be unique, the total number of unique keys (2128 or 3.4028236610

that the probability of the same number being generated twice is very small.

The term GUID usually references Microsoft's implementation of the Universally Uni

(UUID) standard, however, many other software developments and standards includin

term GUID.

Hierarchy A ranking or ordering of abstractions. The two most common hierarchies in a complexits class structure (the "kind of" hierarchy) and its object structure (the "part of" hierar

may also be found in the module and process architectures of a complex system. Hier

the fundamental elements of the object model.


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IFC Specification The whole of IFC Release documentation that includes IFC Object Model in EXPRESthe semantic definitions and explanations, and IFC Property Set definitions.

IFC Toolkit A software library or component that provides software developers for the functionaliwriting IFC product models together with a data access interface for accessing the IFC

IFC Toolkits are used in implementing IFC interfaces or pre- and post-processors for

IFC-Model Note: See IFC Object Model.

IfcXML Definition of IFC Object Model using XML schema language.

IfcXML enables exchange of IFC product data in XML format.

ifcXML data specification defines (using XML schema language) the same data conte

EXPRESS schema, only the specification language is different. ifcXML specificationexchange of IFC product data in XML format.

Implementation In the IFC context, an IFC implementation means applications capability to create anand export IFC Project data.

ISG Implementers SupportGroup

A group within IAI that provides a forum for co-operation and support in implementin

IFC Industry FoundationClasses.

An international specification for product data exchange and sharing for AEC/FM. IF

interoperability between the computer applications for AEC/FM. A subset of IFC is a

ISO/PAS 16739.

Information Data that has been interpreted, translated, or transformed to reveal the underlying mea

Note: See also data, knowledge

IDM Information DeliveryManual

Information Flow In process modeling, exchange of information between activities such that output infoactivity acts as an input information form another activity.


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IFD Information Frameworkfor Dictionaries

An international development of an object library for the AEC/FM industry that is com

and can be used to get more detailed information in and out of your construction desig

An alternative identity for the conceptual model within ISO 12006 Part 3

Information Management Integrating information standards, processes, systems, and technology to enable the exinformation among providers and users in order to support the management objectives

organization.

Information Model Formal definition of information, which defines the elements of information and their

A formal model of a bounded set of facts, concepts or instructions to meet a specified

Synonym for conceptual model

Inheritance A specialization / generalization relationship between entity types, the supertype and swhich the subtype inherits all the attributes and constraints from the supertype. Additi

may have more specific attributes and constraints.

Inheritance Hierarchy The (hierarchical) relationship structure between entity types formed through their inhrelationships (Is-a).

Note: Synonym for the term Class hierarchy.

IGES Initial Graphics ExchangeSpecification

A neutral file format for the exchange of geometry data between CAD systems. The fi

IGES were standardized as ANSI Y14.26M in 1979.

Instance A unique instantiation of an entity type. I.e. creation of a unique instance of an entity attributes of and constraints on the instance are defined by the entity type, and each in

own identity and values for their attributes.

Instantiation Creation of instances of an entity type.

IAI International Alliance forInteroperability

An open consortium to develop, promote and for implementation support of IFC.

ICIS International ConstructionInformation Society

An association of organizations that provides national master specification systems an

information systems for the construction industry.


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IC International Council The highest decision making body within the IAI. Each IAI Chapter has representativ

ISO International Organizationfor Standardization

A network of the national standards institutes of 157 countries.

ISO is a non-governmental organization: its members are not delegations of national g

Many of its member institutes are part of the governmental structure of their countries

by their government. Other members have their roots uniquely in the private sector, h

by national partnerships of industry associations.

Therefore, ISO is able to act as a bridging organization in which a consensus can be re

solutions that meet both the requirements of business and the broader needs of society

needs of stakeholder groups like consumers and users.

Whatever the country, whatever the language, the short form of the organization's nam

ITM International TechnicalManagement

The technical decision making and coordination body within the IAI. Each IAI Chapte

representatives in ITM.

Interoperability In general, the ability of systems to work together.

Ability of computer applications to exchange, share and utilize digital product / proje

AEC/FM projects and over the life cycle of buildings and building information.

Inverse Relationship A definition of a relationship in an inverse direction. The inverse relationship defines cardinality for a relationship in the inverse direction.

ISO 10303 Standard ISO 10303 Product data representation and exchange standard.

An international standard that has defined the basis for product data technologies, and

exchange standards for a number of industry sectors.

ISO 10303-11 Language Formal specification of the EXPRESS data definition language

ISO 10303-21 Format A data exchange format defined by ISO 10303-21 for the exchange of data encoded acEXPRESS data definition standard. Also termed Part 21 format.


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ISO 12006-2 A standard that defines a Framework for classification of information.

ISO 12006-2:2001 is defined by Working Group 2 of ISO TC59/SC13

ISO 12006-3 A standard that specifies a language-independent information model which can be usedevelopment of dictionaries used to store or provide information about construction w

classification systems, information models, object models and process models to be re

within a common framework.

ISO 12006-3:2007 is defined by Working Group 3 of ISO TC59/SC13

ISO TC59/SC13 The ISO Technical Committee/Sub-Committee concerned with the Organization of inconstruction works

ISO TC184/SC4 The ISO Technical Committee/Sub-Committee concerned with Industrial Data.An international standardization subcommittee that works on a family of standards for

and exchange of industrial data. Among other things ISO 10303 standard is developed

subcommittee.

Note: IFC uses base technologies (e.g. EXPRESS and ISO 10303-21 format) from the

standards developed by ISO TC184/SC4 and adapt concepts from a number of standa

within the generic resources set (ISO 10303-4x series).

ISO/PAS 16739 A subset of IFC 2x specification that has an ISO Publicly Accessible Standard status.

IRD Issues and ResolutionsDatabase

A database of IFC Object Model issues resulting from reviews and IAI Model Supporresolutions against the issues.

Key Attribute One attribute or several attributes which provide a unique identification of an entity indatabase.


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Model DevelopmentProject

A project within IAI the purpose of which is to capture information requirements and

extension model to extend IFC into a new domain.

Model Server A computer application that provides a shared model repository, model management fa data access interface to product/project models for multiple, concurrent client applic

net.

Model-Based An approach, e.g. for AEC/FM computer applications, where the target system (e.g. brepresented by a model which then is used as a basis for analysis, creation of presenta

exchange of data.

MSG Modeling Support Group A group, within IAI, of technical experts that are responsible for the IFC Object ModeSpecification integration, development and maintenance.

Multiple Inheritance A form of inheritance where an entity type (class) inherits from more than one direct

nD n-Dimensional A term used to describe an arbitrary number of dimensions of model visualization beydimensions represented by space, time and cost.

Nesting In IFC, a type of composition where the composite element is a composition of elemetype.

Neutral Form A form of data that is independent of individual computer applications. Typically, neudefined by standards or other open specifications.


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Object A collection of data that is handled in applications as a single unit.

In object or product modeling things are modeled as objects, that have attributes (or p

relationships to other objects.

E.g. the building elements of a building may be modeled as objects that have propertie

relationships to other building elements.

Note: Sometimes generally speaking the term object may mean either a class or an ins

If it is necessary to explicitly make the distinction between the two, the latter terms sh

OMG Object ManagementGroup

A consortium originally aimed at setting standards for distributed object-oriented syst

focused on modeling (programs, systems and business processes) and model-based sta

Responsible for the Unified Modeling Language (UML)

OO Object Oriented A modeling / programming paradigm in which things are modeled / implemented as orelationships (and messaging between the objects).

Occurrence Object A unique occurrence of an object that shares the common characteristics of a type objsimilar occurrence objects, but all the occurrence objects have their own existence and

characteristics, such as location. See also Type object for comparison.

Ontology Enable communication between computer systems.

The key ingredients of an ontology are a vocabulary of basic terms and a precise spec

those terms mean.

OGC Open GeospatialConsortium

A non-profit, international, voluntary consensus standards organization that is leading

of standards for geospatial and location based services. The GML standard is particula

this regard.

OGC and IAI have a liaison agreement

Open Standard A standard that is:

created in an open, international, participatory industry process

freely distributed and openly accessible

technology neutral: i.e. its use must not be predicated on any proprietary technolointerface.


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Open System A system with standardized interfaces between its components, and the internal structcomponents are independent of other components.

A system that interoperates through open interfaces, protocols etc. developed and mai

inclusive, open consensus process. Open systems promote application portability, scal

interoperability, diversity, manageability, extensibility, compatibility with legacy com

portability.

Optional Attribute In EXPRESS, an attribute the value of which may be missing.

Note: If the attribute is not optional the value has to be always provided.

Paradigm A pattern or model.

Parameter A variable used for controlling the value of a mathematical function.

Parser A tool used to interpret a text according to a specific language that is described by a serules. The parser finds the language elements in the text and signals any syntactic erro

usually part of interpreters and compilers.

Partial Model Exchange Exchange or export / import of a product model which is only a subset of the total mo

Partial model exchange brings about a set of issues, like change and version managem

referencing objects that are not part of the exchange, to be addressed as comparison to

exchange.

Post-Processor A software module that make a conversion from a neutral form to the software's internform.

Note: Here, pre/post processing is defined from the viewpoint of the data exchange fil

Pre-Processor A software module that make a conversion from the software's internal representationexternal form, which may be defined by an data exchange standard.

Note: Here, pre/post processing is defined from the viewpoint of the data exchange fil

Presentation Defines how the characteristics of an object are presented on a computer screen or in

Process A system of activities, the material and information flows between the activities, activprocess control to produce a result.

Process Breakdown The decomposition of the process into subprocesses and activities.


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Process Chart-Method A process modeling method in which a process is described as activities and material flows between the activities. Characteristic for the method is that each participating ac

"swim lane" for its activities.

Process Model A model that represents the relevant characteristics of a process for a defined purpose

Product Data A representation of information about a product in a formal manner suitable for comminterpretation, or processing by human beings or by computer applications.

Computer interpretable data about product and related things.

For example, information about a building and the construction project stored into an

IFC format.

Product Data Definition A formal definition of product data.

Product data model is an example of product data definition.

Product Data Model An information model for product data.

A formal specification of product data.

For example, IFC Object model is a product data model defined for AEC/FM product

Product Data Technology A set of IT methods, models, standards, toolkits and applications that to support the Inprocesses throughout the life cycle of a product.

Product information Facts, concepts or instructions about a product.

Product Library / PartLibrary

A digital library of product information that computer applications can utilize in produ

For example, furniture manufacturer's product information library for furniture, that thaccess via Internet, and use the product information as part of the building model crea

application.


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Product Model An instantiation of a product data model.

A product model of a specific building represents product data about the building in a

defined by a product data model.

For example, model of a building stored into an exchange file in IFC format.

Product Modeling An art and science that deals with modeling and representation and exchange of produinformation in computer interpretable form.

Product Structure Describes the decomposition of a product from its components.

Project A unique set of work, with limited duration, which has a goal and resources to aim for

Project Data Computer interpretable data about construction projects and the resulting products, th

Project Database A database for project specific data.

Property In general, properties represent qualities and characteristics of something.

In IFC, properties are a generic mechanism and data-driven way of representing charaobjects. i.e. the properties have a name, a value, and may be related to objects.

Property Set Within IFC, a grouping of properties that belong together based on some principle, liklifecycle stage.

PSDML Property Set DefinitionMarkup Language

An XML based encoding for presentation of IFC property sets.

Protocol The agreed-on rules that computers rely on to talk among themselves.

Quantity Data Data that describes quantities like pieces, areas or volumes and is derived typically froof individual objects. Quantity data is often summarized per construction type.

E.g. The area and volume of a wall derived from its basic dimensions, or the total area

construction type.

Reference Model A model that is sufficiently generic and has enough degrees of freedom so that it applmore specific purposes.

Referential Integrity A condition of a database according to which in references all the referred objects also

This means that there are no conflicts (e.g. missing records) in the reference structure

content.


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Select Type An EXPRESS data type that defines alternative data types as its select items.

Semantics Definition of meaning.

Semantic Web A project to create a universal medium for information exchange by putting documentprocessable meaning (semantics) on the World Wide Web.

Set A type of EXPRESS aggregate that can vary in size, in which the elements are not indand the elements are unique (i.e. the same instance cannot occur twice in a set).

Shape Data (dimensionaldata)

Data that defines the shape of an object e.g. the length, width and height of a wall.

Short Form A form of an EXPRESS model which is represented by multiple interrelated schemasmay address a specific subdomain of the model's total scope.

SOAP Simple Object AccessProtocol

A lightweight XML-based messaging protocol used to encode the information in Web

and response messages before sending them over a network.

SOAP messages are independent of any operating system or protocol and may be tran

variety of Internet protocols, including SMTP, MIME, and HTTP.

Simple Type Simple types are the in-built basic data types within the EXPRESS language.

The EXPRESS Simple types are: generic, number, integer, real, string, boolean, logic

types.

Single Inheritance A form of inheritance where an entity type (class) may have only a single supertype.

Software All or part of the programs, procedures, rules, and associated documentation of a datasystem.

Software is an intellectual creation that is independent of the medium on which it is re

Specialization Creation of a subtype for an entity type (the supertype) such that the subtype inherits aand constraints from the supertype, but the subtype may define its own specific attribu

constraints.

SPF SPF-Format STEP Physical File Format.


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State The current set of values of the properties (or attributes) that define an object (i.e. an oentity).

State may also be considered as a memory that may be changed by sending message

SDAI STEP Data AccessInterface

A data access interface designed for repositories containing data configured according

schema.

STEP Standard for TheExchange of Productmodel Data.

A set of international standards under the designation ISO 10303.

Subtype In the entity type inheritance relationship the more specific entity type that inherits prosupertype. Additionally the subtype may define its own specific properties.

Supertype In the entity type inheritance relationship the more generic entity type that may have aspecific subtypes.

Symbol Abstract graphical representations of objects, often used in CAD and CADD systems.

A symbol is also a term in the language to represent a concept or an object in the obje

Syntax Definition of elements of and a grammar for a format.

System An integrated whole that functions through the interrelationships between its compone

Task A piece of work that typically is planned and scheduled as part of a project work and t

Taxonomy The science of classification according to a pre-determined system, with the resulting provide a conceptual framework for discussion, analysis, or information retrieval.

TAG Technical Advisory Group A group within IAI for advising IAI in IFC long term strategies and developments.


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Term The name corresponding to a concept.

Note: "Quadlet": Concept term - definition - referent

Test case An IFC model Instantiation as an IFC exchange file for certification purposes.

In the certification process the candidate applications are tested e.g. using the test case

To-Be Process The future (goal) state of a process.

Note: In comparison, see As-is process.

Topology Connectivity of elements that make up the representation of an object.

Type Generic term for simple types, defined types and entity types.

Type Object An object that represents the common properties shared by a number of occurrence obNote: See also occurrence object.

UML Unified ModelingLanguage

A general-purpose modeling language that includes a standardized graphical notation

abstract model of a system. It is extendable using profiles and stereotypes.

Adopted as a de facto standard by the Object Management Group.

URL Uniform ResourceLocator

A type of identifier that is an address that specifies the location of a file on the Interne

URN Uniform Resource Name A type of identifier for a resource on the Internet that is a globally unique, location-inpersistent name.

Unique List An extension of the EXPRESS LIST aggregate that can vary in size, in which the elemby order, and the elements are unique (i.e. the same instance cannot occur twice in a s

Uniqueness Rule A rule within EXPRESS language that defines that a value of an attribute or combinedattributes have to be unique for each instance of an entity type.

Upward Compatibility A type of compatibility in which the data files based on an earlier specification releasewith data files based on a later specification release.


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WHERE Rule In EXPRESS; a rule within the context of an entity type that defines constraints for althe entity type.

View In general, a subset of, or perspective to the totality from a specific viewpoint or speci

In IFCs, a defined subset of IFC Object Model that a number of implementers have ag

in their implementations.

Virtual Environment A data set describing an environment based upon real-world or abstract objects and daused as a representation of the real world.

Vocabulary A set of terms relevant for a certain domain

OWL Web Ontology Language A language for defining Web ontologys and their associated knowledge bases

Web Services Self-contained, self-describing, modular applications that can be published, located, athe Web. Web services perform functions that can be anything from simple requests t

business processes. Once a Web service is deployed, other applications (and other We

discover and invoke the deployed service.

WSDL Web Services DescriptionLanguage

An XML-formatted language used to describe a Web service's capabilities as collectio

communication endpoints capable of exchanging messages. WSDL is an integral part

XML-based worldwide business registry. WSDL is the language that UDDI uses.

Workflow The automation of a business process, in whole or part, during which documents., infoare passed from one participant to another for action, according to a set of procedural

Workflow ManagementSystem

A system that defines, creates and manages the execution of workflows through the uwhich is able to interpret the process definition, interact with participants and invoke I

XML Schema A definition of representation of information using XML schema language. XML schrepresentation of information for specific purpose, within specific domain.


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XSG XML Support Group A group that existed within IAI, to coordinate ifcXML work. This group is not currenifcXML development activities are now within the scope of the IAI Model Support G

XML eXtensible MarkupLanguage

A language for defining and exchanging structured, computer interpretable informatio

method for both the definition of information, and the encoding of data based on the d

exchange format.

Note: XML schema language is an alternative method to EXPRESS data specification

define product data models like the IFC model, and ifcXML is an alternative data exc

the IFC ISO 10303-21 exchange format.

XSLT eXtensible StyleLanguage Transformation

The language used in XSLstyle sheets to transform XML documents into other XML

XSL processor reads the XML document and follows the instructions in the XSL style

outputs a new XML document or XML-document fragment. This is extremely useful

where the same data need to be converted into different representations of XML. Not

the exact same programs, applications and computer systems.
http://www.webopaedia.com/TERM/X/XSL.htmlhttp://www.webopaedia.com/TERM/X/style_sheet.htmlhttp://www.webopaedia.com/TERM/X/XML.htmlhttp://www.webopaedia.com/TERM/X/XML.htmlhttp://www.webopaedia.com/TERM/X/style_sheet.htmlhttp://www.webopaedia.com/TERM/X/XSL.html


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References

Association for Geographic Information: GIS Dictionary.

http://www.geo.ed.ac.uk/agidict/welcome.html

Avanti. Glossary of Terms. http://www.avanti-construction.com/docs/ICTE%20Glossary.pdf

British Standards Institution. BS6100 series. Glossary of building and civilengineering terms (multiple parts). BSI. London

Canadian forest service. Glossary of knowledge management terms.http://www.nrcan.gc.ca/cfs-scf/science/prodserv/kmglossary_e.html#index

IAI International Alliance for Interoperability. Welcome to the IAIInternational web site. IAI:n kotisivu, URL: http://www.iai-international.org/

ICCI ICT Glossary, European project IST-2001-33022.http://cic.vtt.fi/projects/icci/public.html **

ISO 10303-1:1994. Industrial automation systems and integration Product datarepresentation and exchange Part 1: Overview and fundamental principles.

International Organization for Standardization ISO, Geneva. 17 s.

ISO 10303-11:1994. Industrial automation systems and integration Productdata representation and exchange Part 11: Description methods: The

EXPRESS language reference manual. International Organization for

Standardization ISO, Geneva. 208 s.

Finnish building owner's association. Glossary for real estate business (inFinnish). 2001. 45 s.

Finnish information technology association. EDP-glossary (in Finnish).Talentum. Helsinki 2003. 710 s.

Karstila, Kari. IAI Modeling Support Group. Glossary for IFCs - Draft V0.4.Non-published. 2002. 28 s.

NASA Explores:Glossaries:9-12.http://www.nasaexplores.com/glossary_view_9-12.php

Open Geospatial Consortium Glossary of Terms.http://www.opengeospatial.org/resource/glossary

Wikipedia. http://en.wikipedia.org

** site is no longer maintained and may contain spurious entries
http://www.geo.ed.ac.uk/agidict/welcome.htmlhttp://www.avanti-construction.com/docs/ICTE%20Glossary.pdfhttp://www.avanti-construction.com/docs/ICTE%20Glossary.pdfhttp://www.nrcan.gc.ca/cfs-scf/science/prodserv/kmglossary_e.html#indexhttp://www.iai-international.org/http://cic.vtt.fi/projects/icci/public.htmlhttp://www.nasaexplores.com/glossary_view_9-12.phphttp://www.opengeospatial.org/resource/glossaryhttp://en.wikipedia.org/http://en.wikipedia.org/http://www.opengeospatial.org/resource/glossaryhttp://www.nasaexplores.com/glossary_view_9-12.phphttp://cic.vtt.fi/projects/icci/public.htmlhttp://www.iai-international.org/http://www.nrcan.gc.ca/cfs-scf/science/prodserv/kmglossary_e.html#indexhttp://www.avanti-construction.com/docs/ICTE%20Glossary.pdfhttp://www.avanti-construction.com/docs/ICTE%20Glossary.pdfhttp://www.geo.ed.ac.uk/agidict/welcome.html

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