Overview

A thorough computer representation of an as-built 3D construction site was difficult to create. Defining the as-built description of the construction progress involved three challenges: retrieve geometric data, represent data in 3D computer format, and define the progress by newly made differences.

Construction site monitoring is an on-going process that records and monitors data for immediate and post-construction analysis. 4D technologies have applied databases and 3D modeling tools to create time-based construction descriptions as a means for facilitating inspection. Links have been established between databases and corresponding 3D objects at specific time periods. The 3D models can be reviewed visually in different orientations to reveal construction conflicts early enough to make changes to work schedule. The monitoring of a site and its schedule-related activities require object identification and a thorough record of site occurrences. To achieve this goal, timebased 3D (4D) monitoring focuses on a pre-construction study that allows for better management of a site. However, pre-construction simulations cannot necessarily take into account every incident that might occur to the different parts of a building under construction.

Overlapping point clouds provide advantages for the verification, quantification, and creation of construction data as follows.