Impact of three-dimensional parametric modeling of buildings on productivity in structural engineering practice Rafael Sacks ⁎ , Ronen Barak 1 Faculty of Civil and Env. Engineering, Technion-Israel Institute of Technology, Israel Accepted 7 August 2007 Abstract The transition from two-dimensional drafting to three dimensional modeling of building structures is likely to influence structural engineering design practices in numerous ways. The immediate impact in the early stages of adoption in any design practice will be an increase in productivity in design documentation. On the basis of a benchmark of hours for structural engineering design and detailing of reinforced concrete building structures, and two sets of three-dimensional modeling experiments, the potential productivity gain is conservatively estimated to be in the range from 15% and 41% of the hours required for a project due to improvements in drawing production alone. Unlike two dimensional computer-aided drafting, parametric three dimensional modeling is particularly useful at the early stages of design, where engineering skills are required. Both these effects point to an expected decline in the number of drafting staff in proportion to engineering staff. While overall hours expended will decrease, engineers may account for a greater share of the overall workload, or a new professional role – the structural modeler – may emerge. © 2007 Elsevier B.V. All rights reserved. Keywords: Computer aided design; Reinforced concrete; Productivity; Structural engineering; Three-dimensional models 1. Introduction An understanding of the impacts of parametric three- dimensional (3D) computer modeling of building structures for the full range of structural engineering activities (conceptual design, structural analysis, layout, detailing and fabrication), and the scale of those impacts, is essential for structural engineering design practices to plan their adoption strategies. While 3D modeling for structural analysis using finite element or other methods is common, almost all practices rely on two- dimensional (2D) computer-aided drafting to produce their design documentation. Comprehensive use of the newer paradigm of Building Information Modeling (BIM) [6] has yet to be adopted broadly. The main difference between 3D modeling and 2D drafting is that buildings are modeled rather than drawn [21]. Drawings are no longer the repository for design information, but are rather simply reports of the design information, and their production is almost entirely automated. The impacts already observed in other branches of the architecture, engineering and construction (AEC) industry, such as steel and precast concrete engineering and fabrication, include: reduction of design and drafting errors, shortened lead- times and increased responsiveness to clients, and reduction of direct engineering design and drafting costs as a result of improved productivity [19]. The most relevant and immediate impact from the point of view of an engineering practice, whose primary input is labor hours, is the productivity gain in producing design documents. Little research has been reported on quantifying the benefits of three-dimensional (3D) parametric modeling for structural engineering. Sturts and Griffis claim that some civil engineering design practices have experienced a tenfold increase in productivity since the adoption of CAD, including 3D modeling [25], but this figure is not based on empirical measurement or experimentation. Fully 63% of the 56 respondents to a survey Automation in Construction 17 (2008) 439 – 449 www.elsevier.com/locate/autcon ⁎ Corresponding author. Senior Lecturer, Faculty of Civil and Env. Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel. Tel./fax: +972 4 8293190. E-mail addresses: cvsacks@technion.ac.il (R. Sacks), bim@technion.ac.il (R. Barak). 1 Graduate Student, Faculty of Civil and Env. Engineering, Technion-Israel Institute of Technology, Haifa, Israel 32000. 0926-5805/$ - see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.autcon.2007.08.003