The concept of BIM has existed since the 1970s. The term Building Information Model first appeared in a 1992 paper by G.A. van Nederveen and F. P. Tolman. However, the terms Building Information Model and Building Information Modeling (including the acronym “BIM”) had not been popularly used until Autodesk released the white paper entitled “Building Information Modeling”. Jerry Laiserin helped popularize and standardize the term as a common name for the digital representation of the building process as then offered under differing terminology by Graphisoft as “Virtual Building”, Bentley Systems as “Integrated Project Models”, and by Autodesk or Vectorworks as “Building Information Modeling” to facilitate exchange and interoperability of information in digital format.
According to Laiserin and others, the first implementation of BIM was under the Virtual Building concept by Graphisoft’s ArchiCAD, in its debut in 1987.
The National Building Information Model Standard Project Committee has the following definition:
Building Information Modeling (BIM) is a digital representation of physical and functional characteristics of a facility. A BIM is a shared knowledge resource for information about a facility forming a reliable basis for decisions during its life-cycle; defined as existing from earliest conception to demolition.
Traditional building design was largely reliant upon two-dimensional drawings (plans, elevations, sections, etc.). Building information modeling extends this beyond 3D, augmenting the three primary spatial dimensions (width, height and depth) with time as the fourth dimension (4D) and cost as the fifth (5D), etc. BIM therefore covers more than just geometry. It also covers spatial relationships, light analysis, geographic information, and quantities and properties of building components (for example, manufacturers’ details).
BIM involves representing a design as combinations of “objects” – vague and undefined, generic or product-specific, solid shapes or void-space oriented (like the shape of a room), that carry their geometry, relations and attributes. BIM design tools allow extraction of different views from a building model for drawing production and other uses. These different views are automatically consistent, being based on a single definition of each object instance. BIM software also defines objects parametrically; that is, the objects are defined as parameters and relations to other objects, so that if a related object is amended, dependent ones will automatically also change. Each model element can carry attributes for selecting and ordering them automatically, providing cost estimates as well as material tracking and ordering.
Management of building information models
Building information models span the whole concept-to-occupation time-span. To ensure efficient management of information processes throughout this span, a BIM manager (also sometimes defined as a virtual design-to-construction, VDC, project manager – VDCPM) might be appointed. The BIM manager is retained by a design build team on the client’s behalf from the pre-design phase onwards to develop and to track the object-oriented BIM against predicted and measured performance objectives, supporting multi-disciplinary building information models that drive analysis, schedules, take-off and logistics.
Companies are also now considering developing BIMs in various levels of detail, since depending on the application of BIM, more or less detail is needed, and there is varying modeling effort associated with generating building information models at different levels of detail.
BIM in construction management
Participants in the building process are constantly challenged to deliver successful projects despite tight budgets, limited manpower, accelerated schedules, and limited or conflicting information. The significant disciplines such as architectural, structural and MEP designs should be well coordinated, as two things can’t take place at the same place and time. Building Information Modeling aids in collision detection at the initial stage, identifying the exact location of discrepancies.
The BIM concept envisages virtual construction of a facility prior to its actual physical construction, in order to reduce uncertainty, improve safety, work out problems, and simulate and analyze potential impacts. Sub-contractors from every trade can input critical information into the model before beginning construction, with opportunities to pre-fabricate or pre-assemble some systems off-site. Waste can be minimised on-site and products delivered on a just-in-time basis rather than being stock-piled on-site.
Quantities and shared properties of materials can be extracted easily. Scopes of work can be isolated and defined. Systems, assemblies and sequences can be shown in a relative scale with the entire facility or group of facilities. BIM also prevents errors by enabling conflict or ‘clash detection’ whereby the computer model visually highlights to the team where parts of the building (e.g.: structural frame and building services pipes or ducts) may wrongly intersect.
BIM in facility operation
BIM can bridge the information loss associated with handing a project from design team, to construction team and to building owner/operator, by allowing each group to add to and reference back to all information they acquire during their period of contribution to the BIM model. This can yield benefits to the facility owner or operator.
For example, a building owner may find evidence of a leak in his building. Rather than exploring the physical building, he may turn to the model and see that a water valve is located in the suspect location. He could also have in the model the specific valve size, manufacturer, part number, and any other information ever researched in the past, pending adequate computing power. Such problems were initially addressed by Leite and Akinci when developing a vulnerability representation of facility contents and threats for supporting the identification of vulnerabilities in building emergencies.
Dynamic information about the building, such as sensor measurements and control signals from the building systems, can also be incorporated within BIM to support analysis of building operation and maintenance.
Due to the complexity of gathering all the relevant information when working with BIM on a building project some companies have developed software designed specifically to work in a BIM framework. These packages (eg: Autodesk Revit) differ from architectural drafting tools such as AutoCAD and VectorWorks by allowing the addition of further information (time, cost, manufacturers’ details, sustainability and maintenance information, etc) to the building model.
Non-proprietary or open BIM standards
BIM is often associated with Industry Foundation Classes (IFCs) and aecXML – data structures for representing information. IFCs have been developed by buildingSMART (the former International Alliance for Interoperability), as a neutral, non-proprietary or open standard for sharing BIM data among different software applications (some proprietary data structures have been developed by CAD vendors incorporating BIM into their software).
Poor software interoperability has long been regarded as an obstacle to industry efficiency in general and to BIM adoption in particular. In August 2004 the US National Institute of Standards and Technology (NIST) issued a report which conservatively estimated that $15.8 billion was lost annually by the U.S. capital facilities industry due to inadequate interoperability arising from “the highly fragmented nature of the industry, the industry’s continued paperbased business practices, a lack of standardization, and inconsistent technology adoption among stakeholders”.
An early example of a nationally approved BIM standard is the AISC (American Institute of Steel Construction)-approved CIS/2 standard, a non-proprietary standard with its roots in the UK.
There have been attempts at creating a BIM for older, pre-existing facilities. They generally reference key metrics such as the Facility Condition Index (FCI). The validity of these models will need to be monitored over time, because trying to model a building constructed in, say 1927, requires numerous assumptions about design standards, building codes, construction methods, materials, etc., and therefore is far more complex than building a BIM at time of initial design.
Anticipated future potential
BIM is a relatively new technology in an industry typically slow to adopt change. Yet many early adopters are confident that BIM will grow to play an even more crucial role in building documentation.
Proponents claim that BIM offers:
- Improved visualization
- Improved productivity due to easy retrieval of information
- Increased coordination of construction documents
- Embedding and linking of vital information such as vendors for specific materials, location of details and quantities required for estimation and tendering
- Increased speed of delivery
- Reduced costs
Green Building XML (gbXML) is an emerging schema, a subset of the Building Information Modeling efforts, focused on green building design and operation. gbXML is used as input in several energy simulation engines. But with the development of modern computer technology, a large number of building energy simulation tools are available on the market. When choosing which simulation tool to use in a project, the user must consider the tool’s accuracy and reliability, considering the building information they have at hand, which will serve as input for the tool. Yezioro, Dong and Leite developed an artificial intelligence approach towards assessing building performance simulation results and found that more detailed simulation tools have the best simulation performance in terms of heating and cooling electricity consumption within 3% of mean absolute error.
Explorations are underway to pair computer network users’ personal, private and public authentication choices, geographic mapping systems and evolving cloud computing security architecture models, together, to offer customers of geospatial securitization services intuitive new ways to organize their personal, private and public applications and storage. For individuals, businesses and government authorities who generate and manage building information, new ways to discover, share and work on data, within the context of particular places on earth, will be offered. David Plager, AIA, conjectures that today’s web will give way to tomorrow’s geo-web where data will be structured first by place (eg a postal address) and then by space (Personal (one user), Private (a group of users) and Public (all users).