| 3D Graphic Estimating Applications have been widely applied to assistting the estimating work efficiently and accurately in engineering cost management.With the development of AEC industry,the existing applications exposed its own technical bottleneck and probrms,such as mass work on remodeling or model modification,which cause low working efficiency and massive mistake.As a new concept and technique,Building Information Modeling aims to ensure its interoperability over the Life-cycle of bulidings by realizing infromation shareing and transformation using data standard.However,with the fact that the data processing of quantity takeoff is complicated and redundant,the reliability and the flexibility are too difficult to coexist,the current BIM Application fails to optimize the calculation process and improve the efficiency.Based on the IFC standard,this paper conducts a solution about automatic calculation method of quantity take-off.It helps to realize the irrelevance between quantity calucation,information sources and modeling methods,which can truely optmize the calcalation process and improve its flexibility.By introducing the calculation process of 3D graphics applications and BIM applications,this paper quantificationally summarizes the advantages and disadvantages of these existing methods for quantity take-off with typical case.After analysising these existing methods,it illuminates the information expression and clarifies the algorithn between IFC fils and IFC stardand,including extracting the information,calcalating the joint,deducting the cave and so on.The IFC-based calculation method for typical beam-column model,which demonstrates that the relationships between quantity calculation,BIM software and modeling paths could be irrelevant proves that the solution for IFC-based calcalation method is feasible and able to improve the efficiency and precision of quantity take-off. |
