Virtual flood experience systems, which enable users to vividly experience flooding, are attracting increasing attention as effective tools for communicating flood risks. However, existing systems typically rely on virtual cities that do not correspond to real locations and often lack sufficient photorealism, limiting users' ability to relate scenarios to their own surroundings. Although 360° video-based virtual environments offer a simple and scalable way to visually replicate real-world scenes, effective 3D flood visualization in these environments typically requires 3D building geometry of the target area, which is not readily available in many regions. To address this limitation, we propose a new virtual flood experience framework that integrates 360° videos with 3D models automatically constructed from widely available 2D building footprints. By extruding footprints to plausible heights and spatially aligning the constructed models with 360° videos, our framework enables 3D flood visualization in photorealistic environments without relying on pre-existing city models such as CityGML. We demonstrate the framework in Memuro, Hokkaido, Japan, an area vulnerable to river flooding. A user study with local residents showed that the proposed system enhances users' ability to envision location-specific flood evacuation situations, demonstrating its potential as an effective tool for disaster risk communication and education.

翻译：虚拟洪水体验系统能够让用户身临其境地感受洪水灾害，作为传达洪水风险的有效工具正日益受到关注。然而，现有系统通常依赖于与现实地点不对应的虚拟城市，且常常缺乏足够的真实感，限制了用户将该场景与自身环境相关联的能力。虽然基于360度视频的虚拟环境提供了一种简单且可扩展的方式来视觉再现真实世界场景，但在这些环境中实现有效的三维洪水可视化通常需要目标区域的三维建筑几何数据，而许多地区难以获取此类数据。为解决这一局限性，我们提出了一种新的虚拟洪水体验框架，该框架将360度视频与从广泛可用的二维建筑物足迹自动构建的三维模型相结合。通过将足迹拉伸至合理高度，并将构建的模型与360度视频进行空间对齐，我们的框架能够在无需依赖预存城市模型（如CityGML）的情况下，在照片级真实感的环境中实现三维洪水可视化。我们在日本北海道芽室町（一个易受河流洪水侵袭的地区）演示了该框架。一项针对当地居民的用户研究表明，所提出的系统增强了用户构想特定地点的洪水疏散情景的能力，展现了其作为灾害风险沟通与教育有效工具的潜力。