# End-Users' Augmented Reality Utilization for Architectural Design Review
## 2 Literature Review
### Application of Augmented Reality in the Construction Industry  
The unique features of AR technologies (e.g., enhancing additional virtual information on real-world scenes) have provided new opportunities to improve the existing practices of construction projects. The virtual aspects of AR have great potential for pre-construction stages, as it can imitate risky settings that are difficult to simulate in real construction sites [24]. AR not only provides a virtual construction environment in a risk-free setting but also allows users to interact with their surroundings through a wearable device or screen projection [25]. In addition, the AR can create a spatial relationship between the virtual information and the real space by overlapping new virtual information to the real space. This allows users to have a realistic experience of viewing the augmented virtual building object in a real space. Benefiting from this feature, an AR system can analyze constructability or safety issues by simulating construction processes with a virtual prototype at real construction sites [26]. State-of-the-art AR software and hardware, including hand-held devices or head-mounted devices, achieve a seamless synthesis between the digital and physical world to provide virtual information overlaid in a physical environment [23]. Hand-held AR devices can simply include smartphones and tablets, while head-mounted AR devices can be head-up displays for screens, eyeglasses, contact lenses, and space displays [27]. During a design phase, the combination of AR with BIM models allows users to visualize a proposed 3D model that is merged with a surrounding space [7]. For example, when a digital model is overlaid on the actual site, users get to see the parts of the building (i.e., materials, ductwork, furniture, light fixtures, etc.) as they are intended to be installed in advance. With such functional advantages, AR has been applied in construction research that focuses on design collaboration [6; 10], construction management [8; 28; 29], and safety management [30; 31; 32]. Several studies have shown AR as an effective way of reviewing designed building models [33]. [PERSON] et al. (2007) focused on AR system application to review aesthetic factors (e.g., color and texture), and [PERSON] and [PERSON] (2008) tested an AR system on the design error detection task in the construction stage [34; 35]. Although previous studies have examined the application of AR for various design review tasks, they have focused on the technical aspects of the AR system (e.g., registration algorithms) or its feasibility for design review tasks. As such, there is a lack of investigation for the end-user experience. Thus, project stakeholders still may have trouble finding an appropriate visualization platform to involve end-users in design review activities [36]. To implement AR technology in a design review phase, it is necessary to ensure that the AR experience improves users' level of awareness to building information and level of involvement [37]. In this regard, previous studies have limitations in investigating the quality of presentation and end-user acceptability during AR-based design review activities. Considering AR technologies are increasingly recognized as a new alternative display platform for design information, design review elements, such as color, texture, shape, and volume, should be examined differently based on the type of visualization platform. Additionally, since most of the research is limited to comparing VR or AR with traditional 2D screens respectively, a comprehensive comparison is required for all three display platforms (i.e., 2D screen, VR, and AR) when analyzing its quality of presentation and end-user perception [13; 38]. Furthermore, the usability and user experience of the AR platform, which determines how well end-users can utilize the AR system, should be carefully examined for a practical application in the future.