This study offers a method for creating a representation of an on-going construction site by using a geometric approach. The representation includes the definition of 3D data between the design and construction stages. A method is proposed for using a 3D longrange laser scanner to retrieve information on site occurrences, in order to describe the building construction process based on what really occurs at a site. 3D scans are made in stages or at various time intervals. Retrieved shapes are collected in a discrete manner or in a configuration as a whole. The data collection can be conducted wholly or selectively for key referencing based on registration points. Investigated issues involved are target positioning, identification, retrieval, tracking of objects, behaviour description, characteristic description, and integration of segmental geometric information.