Yo'City：基于自我批判式扩展的个性化无界3D写实城市场景生成

摘要

逼真的三维城市生成对虚拟现实、数字孪生等众多应用至关重要。然而，现有方法大多依赖训练单一扩散模型，限制了生成个性化、无边界城市场景的能力。本文提出Yo'City——一种新型智能体框架，通过调用现成大语言模型的推理与组合能力，实现用户可定制、无限扩展的三维城市生成。具体而言，Yo'City首先采用自上而下的规划策略，构建“城市-区域-网格”层级化结构进行城市概念化设计：全局规划器确定整体布局与功能分区，局部设计器则进一步细化各区域的网格级描述。随后通过“生成-优化-评估”的等距图像合成循环实现网格级三维生成，再经由图像转三维技术完成构建。为模拟持续城市演进，Yo'City进一步引入用户交互的关系引导扩展机制，执行基于场景图谱的距离与语义感知布局优化，确保空间连贯的城市生长。为全面评估方法性能，我们构建了多样化基准数据集，并设计六项多维度量指标，从语义、几何、纹理及布局多维度评估生成质量。大量实验表明，Yo'City在所有评估维度上均持续超越现有先进方法。

English

Realistic 3D city generation is fundamental to a wide range of applications, including virtual reality and digital twins. However, most existing methods rely on training a single diffusion model, which limits their ability to generate personalized and boundless city-scale scenes. In this paper, we present Yo'City, a novel agentic framework that enables user-customized and infinitely expandable 3D city generation by leveraging the reasoning and compositional capabilities of off-the-shelf large models. Specifically, Yo'City first conceptualize the city through a top-down planning strategy that defines a hierarchical "City-District-Grid" structure. The Global Planner determines the overall layout and potential functional districts, while the Local Designer further refines each district with detailed grid-level descriptions. Subsequently, the grid-level 3D generation is achieved through a "produce-refine-evaluate" isometric image synthesis loop, followed by image-to-3D generation. To simulate continuous city evolution, Yo'City further introduces a user-interactive, relationship-guided expansion mechanism, which performs scene graph-based distance- and semantics-aware layout optimization, ensuring spatially coherent city growth. To comprehensively evaluate our method, we construct a diverse benchmark dataset and design six multi-dimensional metrics that assess generation quality from the perspectives of semantics, geometry, texture, and layout. Extensive experiments demonstrate that Yo'City consistently outperforms existing state-of-the-art methods across all evaluation aspects.

Yo'City：基于自我批判式扩展的个性化无界3D写实城市场景生成

Yo'City: Personalized and Boundless 3D Realistic City Scene Generation via Self-Critic Expansion

摘要

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