Comparison of Image-Based and Manual Field Survey Methods for Indoor As-Built Documentation Assessment

Abstract

As-built models and drawings are essential documents used during the operations and maintenance of buildings for managing facility spaces, equipment, and energy systems. Inefficiencies in processing, communicating, and revising as-built documents therefore result in high costs imposed on building owners. Facility managers still rely heavily upon manual surveying procedures for developing and verifying as-built drawings and models. To streamline this often time consuming process, this paper addresses the advantages and limitations of photogrammetry for remote sensing and verification of interior as-built conditions. Two classrooms are captured using photogrammetric image processing software and image-based dimensions are compared to dimensions gathered through a traditional manual survey yielding an average percent error of approximately 2%. Both image-based and manual dimensions are then compared to dimensions extracted from an existing asbuilt BIM model of the interior spaces, and the proposed image-based verification method successfully identifies the same gross errors in the as-built BIM model.