Application of signature-based matching for IFC model comparison

Abstract

The paper highlights the problem of Industry Foundation Classes (ISCs) model comparison in a platform-neutral collaboration of Building Information Models (BIMs). A critical issue in the IFC model comparison is establishing the right candidates for comparison, which typically depends upon using Globally Unique Identifiers (GUIDs). GUIDs are criticised for inconstancies that result because of complex modelling operations and nature of BIM authoring tools that are used to exchange IFC data. This paper presents a signature-matching approach that advocates using dynamic object identities, calculated from the characteristics and attributes of IFC objects, using hash keys that can create a unique signature for an object. Exemplars of creating IFC object signatures are presented. The proposed methodologies for creating IFC object signatures are implemented in a custom-built tool, xBIM Signatures exporter, and are verified using a test case. This research is limited to discussing signatures for IfcBuildingElements and has not considered a level of details and signature weighting of various object characteristics to formulate a robust solution. The proposed signature matching approach can benefit model comparison functionality for model servers and cloud-based collaboration tools.