In recent years, advancements in 3D city models have been instrumental in urban planning and public engagement. In Japan, over 200 cities have adopted open digital twin data in CityGML format as promoted by Project PLATEAU of the Ministry of Land, Infrastructure, Transport and Tourism. This initiative, detailed in Binyu et al.'s research and the 3D City Index report, involves collaboration with the global OpenStreetMap community. Utilizing open database license ODbL, the integration of digital twin data with OpenStreetMap has been explored since 2022, aiming to enhance the global adoption of 3D city models and showcase the benefits of collaborative urban development.