As in every industry, there are technological developments in the construction industry. One such development is Building Information Modelling (BIM). Two-Dimensional (2D) projects can be interpreted differently by stakeholders and discrepancies can go undetected. Consequently, repetitive and inaccurate quantity and cost calculations may occur. BIM allows the representation of a building in three dimensions (3D) using smart objects instead of traditional lines and enables quantity and cost estimations by assigning area, volume and monetary information to these objects. Even if changes are made to the model designed in BIM, quantity and cost will also change automatically. Thus, BIM accelerates the process by reducing the necessity of repeated calculations. With these features, BIM can overcome the problems of traditional methods by providing fast, practical and realistic estimates. In this study, a building was exported from 2D to a BIM based program and modeled in 3D. Quantity and cost calculations were performed using the same program and the process was explained. To determine the accuracy rate of the BIM system, a comparison was made by calculating the cost over the bill of quantities calculated by the traditional method and the ready-made quantity (RMQ) data included in the project. As a result of the comparison, BIM calculated costs were about 7% higher than RMQ and traditional methods. This proves that the idea BIM reduces costs is inaccurate. Rather than reducing costs, BIM provides realistic results.
Güvel et al. (Mon,) studied this question.