Semantics of model views for information exchanges using the industry foundation class schema M. Venugopal a,⇑ , C.M. Eastman b,1 , R. Sacks c,2 , J. Teizer a,3 a School of Civil and Environmental Engineering, Georgia Institute of Technology, 790 Atlantic Dr. N.W., Atlanta, GA 30332-0355, USA b College of Computing and Architecture, Georgia Institute of Technology, 247 Fourth Street N.W., Atlanta, GA 30332-0155, USA c Faculty of Civil and Environmental Engineering, Technion – Israel Institute of Technology, Haifa 32000, Israel article info Article history: Received 17 May 2011 Received in revised form 15 January 2012 Accepted 19 January 2012 Available online 14 February 2012 Keywords: Industry foundation classes (IFC) Model view definitions (MVD) National BIM Standard (NBIMS) Product modeling Process modeling Interoperability abstract The industry foundation classes (IFC) data schema is generic, designed to support the full range of model exchanges needed in the construction industry. For any particular working exchange for some sub- domain of building construction, a set of model view definitions (MVD) is required to specify exactly what information should be exchanged, and in what form and structure the IFC entities are to be used. Defining model view definitions requires principle decisions and workarounds because the IFC itself does not address a number of semantic issues comprehensively. Some of the issues identified and discussed include the typing of objects, instances, geometry, relationships, and rules, which are supported in the IFC schema, and the complexities of exchanging such information accurately between applications. This paper advances the idea of MVD Concepts as an object-oriented and modular mechanism for embedding semantic meaning in model views. We conclude that although the IFC product model schema is richly expressive, it lacks formal definition of its entities, attributes, and relationships. To achieve standardized and re-usable model views, further research towards a modular and logical framework based on formal specification of IFC concepts is recommended. This research is expected to impact the overall interoper- ability of applications in the building information modeling realm. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction The term building information modeling has come to be associ- ated with the digital representation of the physical and functional characteristics of a facility and also the process of creating, using, and maintaining such a shared knowledge resource as a tool for deci- sion making throughout the lifecycle of a facility [37,14]. Architecture, engineering, and construction (AEC) and facilities management (FM) involve domains that require a very diverse set of information and model to be shared. One of the factors influencing the value proposition of BIM in industry is the efficiency of interoperability solutions that provide flawless and streamlined information flow between different disciplines in a project [54]. The past decade has seen the use of BIM as a central, information-management, paradigm gain popularity. Hitherto, lack of interoperability was the issue restricting BIM applications from attaining their full potential. Data exchange was possible only through custom-built translators specific to applications, or manual translation, where the receiver of the information re-builds that information struc- tures in the receiving application. Industry foundation classes (IFCs) provide the building blocks for interoperability through its open and neutral data schema. However, IFC implementations need clear guidance for specific purposes and projects. The authors’ experience in collecting ex- change requirements, developing specifications for exchange mod- els based on IFC and thereby specifying a BIM standard for the precast concrete domain using the NBIMS model view approach, led to new understandings of the benefits of the process, but also to shortcomings, both with the approach itself and with the IFC schema. Various issues such as user interpretation, model view definition issues and IFC schema definitional ambiguities are ad- dressed. Two sets of semantics are at the core of any successful model exchange. One of which is the user or application functional semantics defining the information that must be exchanged and the other being the representational semantics available in IFC or other data modeling schema representing the user intentions. For any particular model exchange there needs to be semantic clarity to issues such as; how does one represent in IFC the type-instance relations? What representation for the shape families? What are the semantics for the patterns of layout such as rebar, tiles, brick 1474-0346/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. doi:10.1016/j.aei.2012.01.005 ⇑ Corresponding author. Tel.: +1 510 579 8656; fax: +1 404 894 2278. E-mail addresses: manu.menon@gatech.edu (M. Venugopal), charles.eastman@ coa.gatech.edu (C.M. Eastman), cvsacks@technion.ac.il (R. Sacks), teizer@gatech.edu (J. Teizer). 1 Tel.: +1 404 894 3477; fax: +1 404 894 2278. 2 Tel.: +972 4 8293190. 3 Tel.: +1 404 894 8269; fax: +1 404 894 2278. Advanced Engineering Informatics 26 (2012) 411–428 Contents lists available at SciVerse ScienceDirect Advanced Engineering Informatics journal homepage: www.elsevier.com/locate/aei