Definition and implementation of temporal operators for a 4D query language

Currently, there is no technology available to validate 4D Building Information Models using formal methods of temporal and spatial analysis. We propose to fill this technological gap by providing a query language which provides dedicated spatial and temporal operators. In the presented approach, a building is digitally represented by an instance of the neutral data format Industry Foundation Classes (IFC). With reference to the temporal and spatial data, the promoted IFC class structure is optimized for the particular query functionality. On the basis of this adapted object model, we make use of the Language-Integrated Query technology (LINQ) provided by Microsoft's.NET framework. As LINQ was originally developed for defining static queries which are evaluated at compile time, we have implemented a dynamic version called Live LINQ in order to allow the user to flexibly formulate queries and to process these during the runtime of the BIM application. The developed interface provides a powerful and easy-to use mechanism for the spatial-temporal analysis and verification of 4D building information models.