Integrated sequential as-built and as-planned representation with D 4AR tools in support of decision-making tasks in the AEC/FM industry

The significant advancement in digital imaging and widespread popularity of digital cameras for capturing a comprehensive visual record of construction performance in the architecture, engineering, construction, and facility management (AEC/FM) industries have triggered an extensive growth in the rate of site photography, allowing hundreds of images to be stored for a project on a daily basis. Meanwhile, collaborative AEC technologies centering around building information models (BIMs) are becoming widely applied to support various architectural, structural, and preconstruction decision-making tasks. These models, if integrated with the as-built perspective of a construction, have great potential to extensively add value during the construction phase of a project. This paper reports recent developments from research efforts in (1)automated acquisition of as-built point-cloud models from unordered daily site photo collections and geo-registration of site images, (2)automated generation of four-dimensional (4D) as-built point-cloud models, and (3)semiautomated superimposition of the integrated as-built model over 4D (three dimensions plus time) BIMs to generate integrated 4D as-built and as-planned visualizations. The limitations and benefits of each modeling approach, the motivations for development of 4D augmented-reality (D 4AR) environments for integrated visualization of as-built and as-planned models, the perceived and observed applications, and the benefits in seven case studies are discussed. Not only does a D 4AR model visualize construction processes and performance deviations, it can also be used as a tool for automated and remote monitoring of progress and safety, quality control, and site layout management, and enables enhanced coordination and communication.