BIM – intelligent building model management
By: Simon Ravn, Building Informatics Engineer MSc.
Building information model(ling) or management better known as BIM, has been a focus point in the Danish Building industry in the past couple of years.
The understanding of what BIM stands for and what it can do, is not fully conceptualised in the industry, and has in the last couple of years been a buzzword for many architectural, engineering, construction, and operation (AECO) companies.
Buzzword aside, BIM as a methodology for selecting, creating/ modelling, and storing data is beneficial. BIM can however be used for more than just decision making in the early design phases [Eastman et al., 2011] [Vestergaard et al., 2012] [MacLeamy, 2004].
By modelling geometry and information in the early phases of design, BIM- models are ready for use in later stages of build and operation, and through many different digital tools.
A key to securing the level of development (LOD) intended by the building information modellers and the amount of data needed for further use of BIM, stored in the model, is defining the LOD in project contracts.
The LOD indicates the degree to which the element geometry and attached data has been thought through and how high the level of visualisation must be [BIMforum, 2017]. Use of BIM demands consideration, to secure an output of the model useable for what is needed by all AECO partners on a project.
BIM is just as much management of data and the modelling process, as it is the model itself.
Ariyaci et al., (2011) argues that implementation and use of BIM is just as much about the humans using it, as well as the processes and technology.
“A BIM is a digital representation of physical and functional characteristics of a facility. As such it serves as a shared knowledge resource for information about a facility forming a reliable basis for decisions during its lifecycle from inception onward” [NBIMS-US, 2015].
This author uses BIM as the “word” describing the process of defining what is needed to design, build, and operate a building and how it must be modelled in a computer aided design (CAD) application, like Revit, ArchiCad or MicroStation i.a, and how it must be stored in a repository for further use.
By this definition BIM is the full process, whilst CAD is the computer aided design or the visual geometry model with attached data.
BIM is not just a representation of the geometry or the data defining the building. BIM also includes data about neighbouring objects and other data needed for e.g. Energy De-sign (ED) calculations, Indoor Environmental (IE) simulations and other building analysis’s done in respect to design and build of new building or renovation projects.
Levels of development
The use of defined LOD’s in the ICT- contract on a building project, can reduce conflicts between project partners. Multiple standards of LOD exist in Denmark, mainly defined by the industry itself. In this regard DiKon must be mentioned. Other standards are: Cuneco which has 7 LOD, and Omniclass defining 15 hierarchical models.
Each type of LOD has is own pros and cons, however, independent on which LOD one uses, data can be secured in the right amount and format, aiding both exchange of data between design and building processes, and between applications.
Interoperability is defined by Ravn (2018) as: “the ability of one system to work with other systems without any effort on the part of the end user of the system”.
Most CAD and BIM applications today support the use of the Industry Foundation Class (IFC). IFC provide the building blocks for interoperability through its non- proprietary data schema [Venugopal et al., 2012]. This means interoperability can be achieved through use of IFC.
Interoperability is needed to use data, modelled and stored in BIM for other analysis’s. Defining the LOD can ensure the right data is exchanged. On the other hand, interoperability ensures exchange is possible.
In this regard IFC is a key format to mention. However, all open formats and standards e.g.: XML (eXtensible mark-up language), PDF (Portable Document Format) and DXF (Drawing Exchange Format) also serves as tools enhancing interoperability.
Intelligent use of BIM
BIM-users often assumes BIM being equal to Revit or the application they use for geometric modelling (CAD). However, Revit and other CAD- applications are “just” the tools for managing geometry and data. BIM is the full process including geometry and data, but especially the further manipulation and storing of said data.
By creating models with a high (data) LOD, lists and schemas of building components are exportable from CAD- applications to text documents (TXT). This can e.g. happen through the application “report” function in Revit. The TXT- file can after export from Revit, be opened in Microsoft Excel for calculation of time and price in Sigma or costume made spreadsheet calculations.
This is not an advanced use of BIM, it is though an intelligent use of the data attainable from the CAD file.
In the design phase of a project, BIM can be used for enhancement of user understanding of the building geometry as well.
Many solutions exist to make enhancement of understanding possible. Virtual Reality (VR) and Augmented Reality (AR) are such tools. These tools visualise Virtual Environments (VE) created on CAD data. VR and AR will not be further discussed in this article, but the basis VE can be used quite easily for enhancement of user understanding.
Through the free Solibri Model Checker, building understanding can be attained, not only for the user, but also for the architect(s) designing the building.
Solibri Model Checker makes it possible to tour a building, and makes the geometry more tangible, which aides decision making. The application reads the IFC format.
The use of such tool is another intelligent use of BIM, based on CAD- data accessible from the design models.
How intelligent the use of the two BIM tools described is, depends on the LOD of the CAD- model, as well as the discipline of the people modelling geometry and data.
This small article has introduced building information model(ling) and management as a tool for design and storing of building data for the whole AECO industry in both new build- and renovation projects.
It has further discussed two ways of intelligently using BIM tools, based on CAD. LOD and interoperability is intertwined tools ensuring exchange of the right data, in the right format.
BIM must furthermore, be created with intention of data sharing, and with data for more than just design, but also for IE and ED analysis’s.
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Ravn, S., 2018. Automated Data Acquisition. Master’s thesis. Department of Civil Engineering, Building Informatics. Aalborg University. (Unpublished).
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