# A Development of Visualization Technology through AR-Based Design Checklist Connection
## 1 Introduction  
### Background and Purpose  
The initial design review in an architectural project has the effect of reducing design changes needed in the later stages of said project by 5-40% [1], and as such, a process of collaboration between architects, clients, and engineers for such a review is very important [2]. Since BIM allows us to check and correct errors [3] in design immediately while viewing the 3D model, the introduction of this technology has greatly facilitated collaboration [4]. In practice, many design reviews (such as interference checks by construction type [5] and 4D simulations [6]) are performed by applying BIM, to improve design quality and performance. However, since the BIM design model displayed on a computer monitor is the one used in much of the design review process, there are limitations in its ability to produce a spatial sense, which often impacts the sense of reality that people have of it [7].  
Recently, design reviews using 3D models designed in VR or AR, beyond simple simulation, have been addressed in many studies [8, 9]. Among them, the metaverse, a higher concept of VR and AR, is an expanded virtual reality and is becoming an ever more important issue in the deep tech realm [10]. The metaverse is not simply a 3D space but a space where the intersection of the real and virtual worlds is reconstructed and fused using 3D technology [11]. Microsoft have built a data center to run a virtual reality space and launched a 'Data Center Virtual Experience Program' that is accessible by everyone [12]. In Korea, a 'Megacity' based on BIM technology was implemented in a virtual space, and a commercial market for digital real estate market was formed. In addition, 'Earth 2', which was reproduced from Google Earth satellite maps and imagery, was implemented as a virtual real estate platform, in which even transactions are possible [13]. As such, VR andAR are effective methods for an intuitive experience of a design proposal because they enhance the user's immersion and sense of reality. Twinmotion, a commonly used software package for rendering, provides via VR the ability to view 3D models designed through game engines in virtual reality. Fuzor also provides a function that allows users to feel realism through avatars using VR and AR [14]. However, the VR and AR functions in currently developed rendering software focus on 3D model exporting [15]. In design review many items including not only design (e.g., shape, material, and scale) but also legislation (e.g., scale, mass) and safety (e.g., barrier-free) should be considered comprehensively. For effective collaboration, the items of law, safety, and design elements considered in design review should be systematized and an interface in which users can review while viewing the design checklist in real time should be established.  
The purpose of this study is, therefore, to develop AR-based design checklist linkage and visualization review technology that facilitates decision making by clients and architects during a design review. For this purpose, a method for linking a design checklist in an AR environment using a game engine (Unity 3D) is proposed and various design review visualization functions are developed with consideration paid to the user interface.