A Comparative Analysis of 2D Computer-Aided Estimating (CAE) and BIM Estimating Procedures

Abstract

Most estimators are trained with, and are used to, manual and Computer-Aided Design and Drafting (CADD) two dimensional (2D) drawings. The spatio-temporal limitations of these designs complicate information management, estimators’ judgments, speed and accuracy. In addition, conventional estimating practices also need to cater to the nuances of diverse standard methods of measurements (SMM) and unstable market conditions. Building Information Modeling (BIM) promises major improvements that overcome the limitations of conventional 2D methods in both design and construction processes. It provides platforms for value integration, robust information sources, simultaneous access to design database, automated quantification, project visualization and simulation, among others capabilities. These capabilities facilitate accuracy, objective risk assessment, comprehensive information management and early integration of cost management principles during design. Arguably, the uptake of Information Technology (IT) in construction is increasing and this discipline-specific study on BIM highlights its considerable potential for improving professional service delivery. Consequently, the integration of BIM and process driven Computer-Aided Estimating (CAE) tools and applications provide robust opportunities for process improvement in Architectural, Engineering, Construction and Facilities Management (AECFM) industries. As part of a research initiative, this chapter reviews the impacts of BIM on cost estimating procedures. In a bid to develop a conceptual framework for underpinning BIM-propelled changes in estimating practice, CAE applications are categorized and compared. Moreover, some features for producing automated quantities from BIMs are compared with provisions of SMM used by estimators. The research concludes with recommendations about the capacity of BIM to revolutionize construction procurement and systems.