BIM-based Process for Managing Property Sets of Objects Extending the IFC Schema

A relevant topic of Building Information Modelling (BIM) deals with interoperability and information exchange based on open formats and information standards. BIM authoring platforms support the import and export of open formats, such as Industry Foundation Classes (IFC). Nowadays, the IFC is the most popular open format used in BIM workflows. However, several challenges still exist due to weak exchange of information, especially when information is created and managed as customised parameters, not included in the IFC Specification, according to different BIM uses. Usually, clients define requirements in separate documents, specifying the needed informative content for Building Information Models (BIModels), and suppliers (e.g. designers, contractors, facility managers) have to manually add required information to BIM objects using BIM authoring platforms. However, interoperability tests have demonstrated difficulties in information exchange. In fact, even if it is possible to customise parameters within BIM authoring platforms, usually such parameters are not correctly transferred into IFC classes and related property sets. Often, they remain affected by the export setting of native formats, causing critical issues on interoperability and data validation. The aim of the paper is to propose and compare different solutions for managing properties within BIM objects extending the IFC schema. In order to reach that goal, a process is defined and tested on a specific BIM use using two different workflows. The identified process deals with: 1) creating property sets and attributes associated to objects; 2) setting values of implemented attributes in the BIM authoring platform; and 3) validating data. The process supports the enrichment of the informative content of BIModels according to open standards for interoperability, showing how some limitations still affect the process when dealing with property sets not included in the buildingSMART IFC Specification.