Quantity Take-Off Methods for Sustainable End-of-Life Strategies: 2D Drawings vs. 3D Scan-to-BIMs

Abstract

The environmental crisis has made it imperative for the construction sector to adopt sustainable end-of-life strategies, such as the reuse of salvaged construction materials. A key factor in deciding on these strategies is accurately quantifying the construction materials in existing structures, a process that can be challenging. This study examines the advantages and limitations of various quantity take-off methods using the Frank Erwin Center (ERC) as a case study. Three approaches are evaluated to determine concrete quantities from the ERC's precast panels façade: (1) manual calculations with printed 2D drawings, rulers, and Microsoft Excel, (2) software-based methods using 2D PDFs drawings and Bluebeam Revu, and (3) creating 3D BIM models from a 3D point cloud (Scan-to-BIM) using Autodesk Recap and Autodesk Revit. By comparing the estimated concrete quantities derived from 2D drawings and the 3D point cloud, the study highlights the strengths and challenges of each method. The findings inform a discussion on selecting an appropriate quantity take-off (QTO) strategy for functionally obsolete structures, guiding decisions for sustainable end-of-life strategies.