# CityBuildAR: Enhancing Community Engagement in Placemaking Through Mobile Augmented Reality
## 2 Literature Background
### M-AR as a Participatory Tool  
M-AR is widely recognized as an effective participatory tool, enhancing interaction, engagement, and understanding across multiple fields by integrating digital components onto physical situations [54]. This technology improves the capacity of individuals and groups to visualize and engage with complex information, particularly beneficial in collaborative and decision-making contexts through mobile devices such as mobile phones, tablets, etc. M-AR is revolutionizing individual and community engagement in projects, conversations, and solutions across sectors such as education, healthcare, design, and public participation [55]. With the extensive use of mobile phones, M-AR transforms conventional decision-making tools into contemporary digital solutions, integrating AR, Virtual Reality (VR), and Geographic Information Systems (GIS) to create interactive, portable platforms for collaborative engagement [42]. Despite its potential, M-AR remains less popular due to technical challenges such as limited device compatibility, high computational demands, and the need for robust internet connectivity [56]. Additionally, its adoption is hindered by a lack of user familiarity, high development costs, and the absence of standardized frameworks, which collectively restrict its widespread implementation and scalability. M-AR has emerged as a powerful participatory planning tool, enabling a more inclusive, interactive, and accessible approach to urban and spatial planning. By overlaying digital elements onto the physical environment, AR enhances visualization, interaction, and comprehension for planning professionals, stakeholders, and community participants [55]. Traditional participatory methods, reliant on static tools like paper maps, drawings, and physical models, often fall short in conveying the complexity and spatial dynamics of urban projects. For instance, MIT's CityScope project integrates AR with 3D physical models to allow stakeholders to collaboratively explore urban scenarios, such as transportation network changes or housing developments, in an understandable format [57]. However, this approach often requires expert assistance for setup and operation, as it involves technical devices like projectors or tablets. This complexity makes it less community-friendly compared to more accessible tools like M-AR platforms, which are easier to use and require minimal technical expertise. AR has been widely used as a participatory tool to engage communities in the urban planning process, providing an interactive platform for understanding and contributing to urban planning initiatives. In Amsterdam, numerous grassroots projects have utilized digital tools, including websites and interactive applications, to enhance citizen engagement in urban development. These technologies empower communities to address urban challenges, cooperate on solutions, and see project outcomes, thereby improving their capacity to provide informed feedback [58]. In Oslo, Norway, AR was used to support community-driven planning for urban green initiatives, including the proposal of planting 100,000 trees. This initiative incorporated participatory activities such as visual presentations, drawings, and AR-enhanced simulations, allowing community members to see and interact with proposed changes in real time [59], and highlighted that AR facilitated community understanding and participation, encouraging meaningful contributions to urban planning processes. Similarly in Bandung City, Indonesia, community members actively participated in data collection and research to identify and address urban planning issues in their local environment [60]. Out of the 33 AR applications found in literature (Table 1), five are relevant to urban planning and community engagement. These applications aim to improve urban design, facilitate community participation, and enhance planning processes through interactive and immersive technologies. A detailed review of these applications is as follows.