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This paper is based on the lead author’s PhD thesis which designed and tested a prototype for exchanging partial sets of Building Information Modeling (BIM) on a cloud-based service. This integrated process would advance key decisions at an early design stage through faster information exchanges and improve best practices during collaborative work that are readily transferred to project teams using Cloud-BIM software. The thesis rationale was influenced through the recognized difficulty of exchanging data at element or object level which depends on the information requiring compatible hardware and software, in order for the data to be read and transferred freely between applications (Alshawi & Ingirige, 2003; Alshawi, 2007). The concept of interoperability allows seamless data exchange, at the software level, among diverse applications with their own internal data structures. The process involves mapping parts of each participating application’s internal data structure to a universal data model and vice versa. The concept is to employ a universal open data structure enabling other applications to become interoperable via mapping and eliminate the costly practice of manually integrating particular applications (NBIMS, 2007).
In the construction industry, Building Information Modeling is the most integrated shared model between all disciplines. It is based on a manufacturing-like process where standardized deliverables are used throughout the life cycle with effective collaboration as its main driving force. The properties of BIM include parametric modeling – providing tabular views of components and characteristic interaction with elements. For example, if a pitch roof changes, so does the walls. It also includes bi-directional co-ordination – enabling virtual simulations of physical construction. However, the dilemma is how to share these properties of BIM applications on one single platform, thus creating a service that would enable the end-user to use multiples of nDs such as, 3D (three dimensional modeling), 4D (time – programming), 5D (costing) and 6D (sustainability) actions asynchronously.
Cloud Computing is a centralized heterogeneous network that enables different applications to be connected to each other. The prospect of using remote data servers with Web service applications provides a mechanism for exchanging data openly. The main exchange format for BIM files is Industry Foundation Classes (IFCs). However, IFC retains the EXPRESS schema, which create documents that are more intricate and voluminous in comparison to an information model optimized for XML. For instance, the following numbers reflect the complex yet schematic richness of building information models (Begley et al. 2005). 800 entities (data objects such as ifcMaterial), 358 property sets; container class that holds properties within a property tree (property sets are assigned to objects (IfcObject) through an objectified relationship - IfcRelDefinedByProperties), and 121 data types (ifcActor such as clients linking with ifcElements).
The proposal in this paper was not to introduce a new schema in contrast to IFC but to re-engineer Simplified Markup Language subsets of XML, in order to exchange partial data sets of intelligent object architecture on an integrated platform that would enhance the BIM usability experience for various disciplines in making key decisions at a relatively early design stage. The concept of using both Cloud computing and BIM originated from the fact that Cloud computing possess four key attributes 1) static features – the interface and commands are roughly the same regardless of where and when the applications are used, 2) standards for data interchange – options for saving data or for importing data are standardized, 3) modular interactivity - the ability to allow one application to interact with another, 4) inter applications communications – the ability of an application to use the service features of another. Sosinsky (2011) and Smith and Tardiff (2009) reiterated these findings insisting that BIM’s cost benefit analysis, for that of structured information that is organised, defined and exchangeable (with these key characteristics computer programming object architecture can be exchanged more successfully), will enhance productivity. The use of a Cloud BIM would enable faster information exchanges between various disciplines at the feasibility design stage of a project.