A model based system for contextual on-site construction planning in augmented reality

The creation of an effective construction schedule is fundamental to the successful completion of a construction project. Effectively communicating the temporal and spatial details of this schedule are vital, however current planning approaches often lead to multiple or misinterpretations of the schedule throughout the planning team. Four Dimensional Computer Aided Design (4D CAD) has emerged over the last twenty years as an effective tool during construction project planning. In recent years Building Information Modelling (BIM) has emerged as a valuable approach to construction informatics throughout the whole life cycle of a building. Additionally, emerging trends in location-aware and wearable computing provide a future potential for untethered, contextual visualisation and data delivery away from the office. The purpose of this study was to develop a novel computer-based approach, to facilitate on-site 4D construction planning through interaction with a 3D construction model and corresponding building information data in outdoor Augmented Reality (AR). Based on a wide ranging literature review, a conceptual framework was put forward to represent software development requirements to support the sequencing of construction tasks in AR. Based on this framework, an approach was developed that represented the main processes required to plan a construction sequence using an on-site, model-based, 4D methodology. Using this proposed approach, a prototype software tool was developed, 4DAR. The implemented tool facilitated the mapping of elements within an interactive 3D model with corresponding BIM data objects to provide an interface for two-way communication with the underlying Industry Foundation Class (IFC) data model. Positioning data from RTK-GPS and an electronic compass enabled the geolocated 3D model to be registered in world coordinates and visualised using a head-mounted display fitted with a forward-facing video camera. The scheduling of construction tasks was achieved using a novel interactive technique that negated the need for a previous construction schedule to be input into the system. The resulting 4D simulation can be viewed at any time during the scheduling process, facilitating an iterative approach to project planning to be adopted. Furthermore, employing the IFC file as a central read/write repository for schedule data reduces the amount of disparate documentation and centralises the storage of schedule information, while improving communication and facilitating collaborative working practices within a project planning team. Postgraduate students and construction professionals evaluated the implemented prototype tool to test its usefulness for construction planning requirements. It emerged from the evaluation sessions that the implemented tool had achieved the essential requirements highlighted in the conceptual framework and proposed approach. Furthermore, the evaluators expressed that the implemented software and proposed novel approach to construction planning had potential to assist with the planning process for both experienced and inexperienced construction planners. The following contributions to knowledge have been made by this study in the areas of 4D CAD: construction applications of augmented reality and BIM; 4D Construction Planning in Outdoor AR; the development of a novel 4D planning approach through decomposition; the deployment of IFCs in AR; leveraging IFC files for centralised data management within real time planning and visualisation environment.