Using termination points and 3D visualization for dimensional control in prefabrication

To increase productivity, quality, and safety, heavy industrial construction projects are increasingly adopting prefabrication and modularization techniques. This shift, in turn, has resulted in fabrication shops fabricating more complex assemblies with tighter tolerances. However, most measurement in these shops is conducted using manual hand measurement tools, which can be costly and is known to cause significant rework due to geometric noncompliance of termination points in particular. Termination points are defined as the coordinate system points where assemblies connect or are constrained. Automated, 3D-scanning measurement and visu-alization systems can potentially be accurate, repeatable, and objective sources of termination point data. In this paper, a new framework for classification and calculation of termination points is presented that is based on automated, 3D-scanning measurement and visualization. The utilization of the framework enables fabrication shops and project owners to adopt effective 3D measurement solutions. To investigate the usefulness of the defined framework, a termination-point-based scan-vs-BIM method is developed for objects with circular cross sections, such as pipe spool assemblies. The method was validated in an industrial-scale experimental study. The study demonstrated that the new framework can be used to develop applications that are more accurate and provide superior visualization to craft workers during fabrication, and thus potentially improve produc-tivity and reduce rework.