# Situated AR Simulations of a Lantern Festival Using a Smartphone and LiDAR-Based 3D Models
## 2 Research Purpose and Methodology  
For a lantern festival held in the evening with crowds, the current study aimed to determine if large-scale documented 3D data can be applied in AR interactions or to assist planning [57] in professional design practice. Moreover, we aim to investigated whether various planning flexibilities of AR interactions can be conducted in a ready-made or customized environment, whether convenient mobile devices, such as smartphones, can be applied in AR, and whether human characters can be applied as a part of a scene by increasing the involvement of the surrounding crowds in AR. This research intended to represent and reconstruct a cultural festival. The representation required appropriate 3D documentation to retrieve and identify significant settings of the scene. The reconstruction of old scenes concerns related context applications in terms of the correlations and interactions of installations in different types and scales. The exemplification should also be applicable to traditional festivals held in the past. We proposed LiDAR-based 3D data and an AR app for supporting documentation and interaction in the representation and reconstruction. The 3D entities should be interacted with using a convenient smartphone and app for different scenarios with matching contexts. Cloud access of a ready-made decimated point cloud or mesh models should enable the app to be implemented under a homogeneous and heterogeneous combination of contexts, as an extension to 3D sustainability. This study should not only develop an app, but also restructure a cultural event for the feasibility of context adaption. The representation of cultural heritage as a single object differs from that of an event, which consists of urban fabrics, installations, facilities, supporting structures, and visitors. The introduction of an entity should be represented with a collection of multiple correlations in an arrangement of a spatial structure. The correlation forms the complexity of the scene and the AR to be applied. Challenges exist in presenting a contemporaneous traditional event, concerning how to define related elements, establish correlations, and create media to determine pertinent relationships between factors. As-built data from real scenes should be utilized to support the illustration of details and spatial structure to a level that establishes a synergistic relationship with the AR application. Reverse engineering should also be implemented with approaches, processes, and expected outcomes to interpret the unique case of a festival, instead of inspecting original design plans. A verification of the simulation was performed by the reconstruction of a 3D model in an AR loop process of interaction, reconstruction, and confirmation. A series of screenshots were recorded for the second photogrammetric modeling of a 3D printed model to study the manipulated result. The novelty of this research was the application of AR in a cultural festival, with data originating from a relatively large size of point cloud. This app should offer models with higher documented reality. The 3D entities should be interacted with using a convenient smartphone and app for different scenarios with matching contexts. Tests by the researchers should be conducted at the original site and in a different locations as a situated application. Test opinions should give the verification of the applications, such as re-experiencing a former event, enabling the display or 3D layout of the context like a canopy with an on/off option, and its successes and restrictions. One of the main purposes of this article is to discuss the feasibility of the application, and the survey of user experience will be the focus of the second stage in the future.