Building information modeling (BIM) is the process of generating and managing building data during its life cycle[1]. BIM involves representing a design as 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 for extracting different views from a building model for drawing production and other uses. These different views are automatically consistent – in the sense that the objects are all of a consistent size, location, specification – since each object instance is defined only once, just as in reality. Drawing consistency eliminates many errors.[2]. Typically it uses three-dimensional, real-time, dynamic building modeling software to increase productivity in building design and construction.[2].The process produces the Building Information Model (also abbreviated BIM), which encompasses building geometry, spatial relationships, geographic information, and quantities and properties of building components. Pieces can carry attributes for selecting and ordering them automatically, providing cost estimates and well as material tracking and ordering.[2].This method of management is more practical and efficient. It eliminates many of the uncertainties found during the construction phase since they can be found during the design phase of the project and fixed so they do not occur during the actual construction phase. Also, any changes during construction will be automatically updated to BIM and those changes will be made in the model. Modern BIM design tools go further. They define objects parametrically. That is, the objects are defined as parameters and relations to other objects, so that if a related object changes, this one will also.[2].
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Phil Bernstein, an FAIA architect and industry strategist, first used the acronym BIM for "building information modeling." Jerry Laiserin then helped popularize and standardize the term [3] 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 Autodesk as "Building Information Modeling" to facilitate exchange and interoperability of information in digital format. According to him[4] and others[5], the first implementation of BIM was under the Virtual Building concept by Graphisoft's ArchiCAD, in its debut in 1987.
Building information modeling covers geometry, spatial relationships, light analysis, geographic information, quantities and properties of building components (for example manufacturers' details). BIM can be used to demonstrate the entire building life cycle, including the processes of construction and facility operation. 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. Dynamic information of 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 [6].
Under the guidance of a virtual design and construction project manager (VDC) BIM can be seen as a companion to Product Lifecycle Management(PLM), since it goes beyond geometry and addresses issues such as cost management, Project Management and provides a way to work concurrently on most aspects of building life cycle processes.
BIM goes far beyond switching to a new software. It requires changes to the definition of traditional architectural phases and more data sharing than most architects and engineers are used to.
BIM is able to achieve such improvements by modeling representations of the actual parts and pieces being used to build a building. This is a substantial shift from the traditional computer aided drafting method of drawing with vector file-based lines that combine to represent objects.
The interoperability requirements of construction documents include the drawings, procurement details, environmental conditions, submittal processes and other specifications for building quality. It is anticipated by proponents that VDC utilizing 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. For example, a building owner may find evidence of a leak in his building. Rather than exploring the physical building, he may turn to his BIM 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 et al. when developing a vulnerability representation of facility contents and threats for supporting the identification of vulnerabilities in building emergencies[7]
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.
The American Institute of Architects has further defined BIM as "a model-based technology linked with a database of project information"[1], and this reflects the general reliance on database technology as the foundation. In the future, structured text documents such as specifications may be able to be searched and linked to regional, national, and international standards.
"The production of a Building Information Model (BIM) for the construction of a project involves the use of an integrated multi-disciplinary performance model to encompass the building geometry, spatial relationships, geographic information, along with quantities and properties of the building components. The virtual design to construction project manager (VDC – also known as VDCPM) is a professional in the field of project management and delivery. The VDC is retained by a design build team on the clients’ behalf from the pre-design phase through certificate of occupancy in order to develop and to track the object oriented BIM against predicted and measured performance objectives. The VDC manages the project delivery through multi-disciplinary building information models that drive analysis, schedules, take-off, and logistics. The VDC is skilled in the use of BIM as a tool to manage and assess the technology, staff, and procedural needs of a project. In short the VDC is a contemporary project managing architect who is equipped to deal with the current evolution of project delivery. The VDC acts as a conduit to bridge time tested construction knowledge to digital analysis and representation."[8][9]
The use of BIM goes beyond the design phase of the project and takes an important role during the construction phase of a project as well as the post construction phases and facility management. The entire purpose of BIM was to make the construction process more efficient and eliminate as many uncertainties as possible before starting the construction process. Participants in the building process are constantly challenged to deliver successful projects despite tight budgets, limited manpower, accelerated schedules, and limited or conflicting information. Innovations in BIM boast of capabilities to ease the pain of project delivery.The concept of Building Information Modeling is to build a building virtually prior to building it physically, in order to work out problems, and simulate and analyze potential impacts.[10]. Furthermore, along the project anticipation and ease of project delivery, the overall safety of the project will improve due to the elimination of uncertainty.The work site is safer because more items will be pre-assembled off site and trucked to the site keeping the on-site trades to a minimum. Waste will be minimized on-site and products will be delivered when needed and not stock piled on site.[10]This will make a great impact in the way a construction project is managed and will also bring along a safer jobsite and more accurate construction with a more sophisticated design process which will allow sub contractors from every trade to input critical information into the software before the beginning of the actual construction.
The Institute for BIM in Canada (IBC) leads and facilitates the coordinated use of Building Information Modeling (BIM) in the design, construction and management of the Canadian built environment. Its founding partner organizations represent specific industry sectors that have a keen interest in seeing BIM implemented in a way, and at a pace, that enables the primary stakeholders to understand their roles and responsibilities and to assess their capacity to participate in this process. IBC’s priorities include an awareness program, a practice manual, a bibliography of useful resources, and a full environmental scan/assessment on the use of BIM in Canada and internationally.
In the UK, CPIC, responsible for providing best practice guidance on construction production information and formed by representatives of the major UK industry institutions, has proposed a definition of Building Information Modelling for adoption throughout the UK construction industry and has invited all UK industry parties to discuss it in order to ensure an agreed starting point. The proliferation of interpretations of the term currently hampers the adoption of a working method that will drastically improve the construction industry and the quality and sustainability of the deliveries from the design and construction team to clients.
The National Building Specification, owned by the Royal Institute of British Architects (RIBA) published The Building Information Modelling Report in March 2011 – an in-depth piece of research into BIM adoption in the UK. At a roundtable discussion in May 2011 UK Government Chief Construction Advisor Paul Morrell called for BIM adoption on UK government construction projects of £5million and over. Morrell also told construction professionals to adopt BIM or be "Betamaxed out".
In June 2011 the UK government published its Building Information Modelling (BIM) Working Party Strategy – This report announced the Government's intention to require collaborative 3D BIM (with all project and asset information, documentation and data being electronic) on its projects by 2016.
The Associated General Contractors and contracting firms also have developed a variety of working definitions of BIM that describe it generally as "an object-oriented building development tool that utilizes 5-D modeling concepts, information technology and software interoperability to design, construct and operate a building project, as well as communicate its details." 5-D modeling concepts involve modeling not only the 3 primary spatial dimensions of X, Y, and Z; but also time as the 4th dimension and cost as the 5th.
Although the concept of BIM and relevant processes are being explored by contractors, architects and developers alike, the term itself is under debate[11], and it is yet to be seen whether it will win over alternatives, which include:
BIM is seen to be closely related to Integrated Project Delivery (IPD) where the primary motive is to bring the teams together early on in the project. [12]. A full implementation of BIM also requires the project teams to collaborate from the inception stage and formulate model sharing and ownership contract documents.
BIM is often associated with IFCs (Industry Foundation Classes) and aecXML, which are data structures for representing information used in BIM. IFCs is developed by buildingSMART (International Alliance for Interoperability). Other data structures are proprietary, and many have been developed by CAD firms that are now incorporating BIM into their software. One of the earliest examples 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.
Proponents claim that BIM offers:
In August 2004 the US National Institute of Standards and Technology (NIST) issued a report entitled "Cost Analysis of Inadequate Interoperability in the U.S. Capital Facilities Industry" (NIST GCR 04-867 (PDF), which came to the conclusion that, as a conservative estimate, $15.8 billion is lost annually by the U.S. capital facilities industry resulting from inadequate interoperability due to "the highly fragmented nature of the industry, the industry’s continued paperbased business practices, a lack of standardization, and inconsistent technology adoption among stakeholders".
In France, several bodies are pushing for a more integrated adoption of BIM standards, in order to improve software interoperability and cooperation among actors of the building industry. Examples are the FFB (Fédération française du bâtiment), or the French arm of buildingSMART International who are supporting IFCs.
On the other hand, software editing companies such as Vizelia were early adopters of IFCs and can now benefit from the full potential of BIM in the Green Building fast-emerging business.
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.
BIM provides the potential for a virtual information model to be handed from Design Team (architects, surveyors, consulting engineers, and others) to Contractor and Subcontractors and then to the Owner, each adding their own additional discipline-specific knowledge and tracking of changes to the single model. The result greatly reduces the information loss that occurs when a new team takes "ownership" of the project as well as in delivering extensive information to owners of complex structures. It also prevents errors made by design team members as well as the construction team (Contractors and Subcontractors) by allowing the use of conflict detection where the computer actually informs team members about parts of the building in conflict or clashing, and through detailed computer visualization of each part in relation to the total building. As computers and software become more capable of handling more building information, this will become even more pronounced than it is in current design and construction projects. This error reduction is a great part of cost savings realized by all members of a project. Reduction in time required to complete construction directly contributes to the cost savings numbers as well. It's important to realize that this decrease can only be accomplished if the models are sufficiently developed in the Design Development phase.
The Industry Foundation Classes (IFC/ifcXML) are an open specification for Building Information Modeling and are used to share and exchange BIM in a neutral format among various software applications. 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 [13] 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.
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