CAAD Futures 2011 : Designing Together, ULg, 2011 © P. Leclercq, A. Heylighen and G. Martin (eds) 403 Automated Cost Analysis of Concept Design BIM Models ABDELMOHSEN Sherif, LEE Jinkook and EASTMAN Chuck College of Architecture, Georgia Institute of Technology, Atlanta, GA, USA sherif.morad@gatech.edu, jklee@gatech.edu, charles.eastman@coa.gatech.edu Abstract. This paper introduces the Preliminary Concept Design (PCD) Cost Analysis Module developed for the General Services Administration (GSA) and the analysis results of a case study involving a concept design courthouse BIM model. The module uses IFC data from BIM models to extract quantity take off data using Solibri Model Checker (SMC), generates an input XML file to the PACES cost estimating software, and produces a comprehensive reporting scheme. The paper explores interoperability issues related to integrating design and analysis tools; specifically BIM models and cost models. We argue that architects and estimators can benefit from the proposed module, where the cost feedback cycle becomes more efficient and their decision-making process is continuously informed throughout multiple design iterations. 1. Introduction Cost analysis for architectural projects is a complex process performed usually intuitively by estimators based on expertise and historical data. The process involves generating estimates for a given project using calculated building quantities. Traditionally, estimators used architects’ design intent drawings to generate datasets for the estimates. In their assessment, they relied on manual take off using 2D drawings, on screen take off from PDFs or CAD drawings, or custom built spreadsheets. This process proved to be exhaustively time consuming, error prone and mostly inaccurate. In architectural practice, this meant a feedback process not prompt enough for design decision-making, where estimates were generated in seclusion from and near the end of the design process. Feedback from estimators could not respond then to the required timeframe of frequently changing design decisions or multiple alternatives.