Abstract: As a new concept and technology, Building Information Modeling is raising a new
revolution in AEC/FM (architecture, engineering, construction and facility management) industry.
However, the reliability and the flexibility of quantity calculation using BIM technology are difficult
to coexist due to the complexity of data processing, the current BIM application fails to optimize the
calculation process and improve the efficiency. Based on the IFC standard, this paper conducts a
research about automatic calculation method of quantity. By analyzing the IFC-based expression of a
typical beam-column joint and formulating the geometric equations of the related components, the
overlap volume of beam-column which will meet the requirements of GB50500-2013 can be
calculated automatically. This research proves that the IFC-based calculation method is feasible and
able to improve the efficiency and precision of quantity take-off, which also demonstrates that the
quantity take-off method can be irrelevant with BIM software and modeling paths.

Key words: IFC, quantity take-off, beam-column joint