# Situated AR Simulations of a Lantern Festival Using a Smartphone and LiDAR-Based 3D Models
## 1 Introduction  
Festivals have been categorized as a form of Intangible Cultural Heritage (ICH) [1; 2; 3] and promoted by different governments, organizations, and media [4; 5; 6; 7]. A lantern festival not only constitutes an important cultural asset, but also creates dynamic interactions with the urban fabric. The festival setting generates a temporary fabric, which is usually removed after the event and deserves both documentation and dissemination. For physical installations, related studies have been undertaken focusing on photogrammetry modeling [8], interactive systems [9], augmented reality (AR)/virtual reality (VR)/mixed reality (MR) [10], and 3D printing [11], in which devices, such as 3D scanners [12; 13; 14], low-cost 3D scans using Google Tango(r) (2014, Google Inc., Mountain View, CA, USA) tablets [15; 16], smartphones or handheld devices [17], and unmanned aerial vehicles (UAV) and light detection and ranging (LiDAR) [18], have been applied with different levels of efficiency and effectiveness. The photogrammetry models were created by applying multi-sourcing [19] or crowdsourcing [20], or in a collaborative manner [21]. Moreover, virtual humans [22], virtual crowds [23], large populations [24], video data of real actors [25], and cartoon-like characters [26] were applied to attract users' interest or as a way to promote communication. These applications have been proven to be feasible for varied cases [27; 28; 29; 30; 31] and scales [32; 33], with awareness of location and context [34]. The documentation is related to information systems [35] and as part of a communication model [36] for exploration and dissemination [37]. Engagement and learning were also assessed [38]. Point clouds have been applied to create mesh models for AR application [39]. Current technology already enables automatic documentation and registration at the size of a backpack for terrains that are unreachable by vehicle. Although Light Detection andRanging (LiDAR) scans can apply a Global Positioning System (GPS) and Inertial Measurement Unit (IMU) on a vehicle for city model reconstruction [40], a static scan is usually applied for a superior scan and registration result. The modeling effort in conversion, meshing, and hole-filling should be alleviated by the direct utilization of a point cloud in AR, regardless of its limits in transparency, larger file size, and the interference of other objects during the scan process. Indeed, a well-sampled and well-textured point cloud model provides a convincing effect with the high resolution of an as-built scene. AR-related applications have been successfully implemented in navigation, education, industry, and medical practice [41; 42; 43; 44]. They combine, register, and interact with real and virtual information in a real environment [45; 46; 47]. Reality with an interactive and highly dynamic experience can be explored using mobile AR applications for layers of information [48; 49]. Considering a case study of a local lantern festival formerly applied to a communication model [50], engagement can be facilitated with improved comprehension through interactions with 3D scenes or entities in AR. To recall a festival that comprises a complicated setting, AR should be applied so that the representation of the past virtual environment can be enriched to achieve a vivid tourism experience. AR applies 3D models in different environments for meaningful context elaboration. The interactive models are usually applied to different sites to fulfill aims in pedagogy or professional practice. The models, which are presented as part of a general structure with no specific preference or constraint, may require re-construction or re-framing of a scene for a specific task. Management issues arise for models, or their instances, with matching backgrounds. The reconstruction of appropriate scenes has proven to be highly beneficial in pedagogy with real-time streaming of contents. Mixed Reality (VR and AR) has also been applied for cultural heritage for the benefits of both [51].