Terms and Definitions

In order to understand the building SMART concept, it is necessary to learn the key terms and abbreviations. Some of the most important are listed on this page.

Term

Acronym

Definition

Building Information Modelling

BIM

Building Information Modelling (BIM) is a new approach to being able to describe and display the information required for the design, construction and operation of constructed facilities. It is able to bring together the different threads of information used in construction into a single operating environment thus reducing, and often eliminating, the need for the many different types of paper document currently in use. To use BIM effectively however, and for the benefits of its use to be released, the quality of communication between the different participants in the construction process needs to be improved.
If the information needed is available when it is needed, and the quality of that information is appropriate, then the construction process can be improved. For this to happen, there must be a common understanding of building processes and of the information that is needed for and results from their execution. The Industry Foundation Classes (IFC) provides a comprehensive reference to the totality of information within the lifecycle of a constructed facility. It has been created as an integrated whole in response to the identification of business needs expressed by the international building construction community. It does not contain a comprehensive reference to individual processes within building construction.
The case for a comprehensive reference to processes in building construction is clear and compelling. By integrating information with the process, the value of such a reference is greatly enhanced and it becomes a key tool in really delivering the benefits of BIM.

Information Delivery Manual

IDM

The Information Delivery Manual (IDM) aims to provide the integrated reference for process and data required by BIM.
The IDM will provide the integrated comprehensive reference required by identifying the discrete processes undertaken within building construction together with the information that is required for and results from their execution.

The IDM will target both BIM users and solution providers:
- For BIM users, it will provide a simple to understand, plain language description of building construction processes, the requirements for information to be provided to enable the process to be carried out successfully, additional information that may need to be provided by the user and the expected end results of the process.
- For BIM solution providers, it will identify and describe the detailed functional breakdown of the process and the IFC capabilities needing to be supported for each functional part in terms of the entities, attributes, property sets and properties required.

Additionally, the IDM will provide an improved methodology for development of future extensions to the IFC model that will include close descriptions of business requirements and IFC support so as to support accelerated implementation.

Industry Foundation Class

IFC

The Industry Foundation Classes (IFC) specification is a neutral data format to describe, exchange and share information typically used within the building and facility management industry sector (AEC/FM). The IFC specification is developed and maintained by buildingSMART International (formerly known as International Alliance for Interoperability (IAI)).
The IFC specification is written using the EXPRESS data definition language, defined as ISO10303-11 by the ISO TC184/SC4 committee. It is the same data definition language as used e.g. in STEP or CIS/2. It has the advantage of being compact and well suited to include data validation rules within the data specification. The IFC exchange file structure (the syntax of the IFC data file with suffix ".ifc") is the so called "STEP physical file" format, defined as ISO10303-21 by the same ISO TC184/SC4 committee. It is an ASCII file format used to exchange IFC between different applications.
In addition to the IFC-EXPRESS specification an ifcXML specification is published as well (since the IFC2x release). The ifcXML spec is provided as an XML schema 1.0, as defined by W3C. The ifcXML exchange file structure (the syntax of the IFC data file with suffix ".ifcXML") is the XML document structure. The XML schema is automatically created from the IFC-EXPRESS source using the "XML representation of EXPRESS schemas and data", defined as ISO10303-28 ed. 2. This ensures that both IFC-EXPRESS and ifcXML handle the same data consistently and that the *.ifc and *.ifcXML data files can be converted bi-directionally.

Model View Defintion

MVD

An IFC View Definition, or Model View Definition, MVD, defines a subset of the IFC schema, that is needed to satisfy one or many Exchange Requirements of the AEC industry. The method used and propagated by buildingSMART to define such Exchange Requirements is the Information Delivery Manual, IDM (also ISO/DIS 29481).
An IFC Model View Definition defines a legal subset of the IFC Schema (being complete) and provides implementation guidance (or implementation agreements) for all IFC concepts (classes, attributes, relationships, property sets, quantity definitions, etc.) used within this subset. It thereby represents the software requirement specification for the implementation of an IFC interface to satisfy the exchange requirements.
Whereas the general exchange requirement is independent of a particular IFC release, the realization (or binding) within the model view definition is specific to an IFC release.
Model View Definitions are either defined within buildingSMART International, or by other organizations and interest group. MVD's defined externally are not considered as buildingSMART MVD's until they are submitted to buildingSMART International, reviewed by the buildingSMART teams and finally accepted.

Exchange Requirements

See --> MVD

Implementer Agreements

In many cases the IFC-specification offers alternatives for support by software applications. Even after limtting the scope by MVDs several alternatives and ambiguities remain. In this case software implementers within the Implementer Support Group are defining agreements to implement the scope of an MVD in a unique way.

International Framework for Dictionaries

IFD

International Framework for Dictionaries (ISO 12006-3) is a library with terminology and ontologies assisting in identifying the type of information being exchanged. It is developed with the purpose of adding value to the IFCs and is language and culture independent.
The International Framework for Dictionaries (IFD) (ISO 12006-3) standard is developed by ISO TC 59/SC 13/WG 6. Many of the members of the work group are also members of International Construction Information Society (ICIS ). The IFD standard has many similarities with the EPISTLE standard for the Oil and Gas industry.
While the IFC standard describes objects, how they are connected, and how the information should be exanged and stored, the IFD standard uniquely describe what the objects are, and what properties, units and values they can have. IFD provides the dictionary, the definitions of concepts, the relationships between them and the common understanding necessary for the communication to flow smoothly.

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