Improvement of realism of 4D objects using augmented reality objects and actual images of a construction site

Many construction firms have begun carrying out schedule management by using digital methods, such as 3D CAD and building information model (BIM)s. However, such methods are hampered by discrepancies between virtual models and real world models. This study develops an augmented reality (AR)-based 4D CAD system, which connects 4D and 5D objects with a real field image and an AR object. A method to link 4D objects and AR objects is proposed in order to implement several types of schedule information, as well as to enable the use of constantly changing schedule information through AR objects. Furthermore, a method for implementing AR objects based on connecting real-time field images is presented to help long distance managers become more accustomed to virtual objects and to enable better reflecting field environmental conditions in schedule management. In this study, the AR-based 4D CAD system using these methods is suggested and applied in a case study to verify the applicability of the system. The proposed system can be used for field monitoring for schedule management at job sites and to support cooperation and decision making between long distance managers and field engineers.