Abstract
This research introduces a three-dimensional (3D) building learning and generation framework based on graph theory and generative AI models, Building-Graph-AI. The framework aims to encode 3D building models into graph-structured data suitable for training graph neural networks (GNNs) and to generate layered 3D models at the detailed building component level. We test various encoding methods and neural networks, selecting the most effective method and defining it as Graph-BIM encoding. The results demonstrate that the Graph-BIM encoding method can reconstruct and generate detailed 3D building models from simple geometries and constraints. Compared to existing methods based on voxel, point cloud and 3D field, Building-Graph-AI excels in learning and generating detailed, hierarchical 3D models at the building component level, such as walls, columns and floors. By bridging the gap between geometric design and AI-based training and generation, this framework enhances the adaptability and efficiency of AI applications in architectural design.