Image-based 3D reconstruction has made significant progress in typical scenarios, achieving high fidelity in capturing intricate textures. However, in the Architecture, Engineering, and Construction (AEC) design stages, existing technologies still face considerable challenges, particularly in handling specific window-to-wall ratios, ensuring window detail consistency, and enabling interactive editing. To address this research gap and encourage greater community attention on this practical architectural design problem, we propose a new task: Editable and Consistent Single-View 3D Reconstruction of Buildings with Specific Window-to-Wall Ratios. To accomplish this: 1) We introduce the ArchiSet dataset, the first public, real-world architectural design dataset, including 13,728 3D building forms in the format of point clouds, voxels, meshes, and window-to-wall ratio information, providing comprehensive support for 3D architectural design research. The dataset also contains over 1,482,624 images in three types—sketches, color block diagrams, and renderings—accompanied by paired window masks for detailed evaluation. 2) We evaluated state-of-the-art single-view 3D reconstruction algorithms on ArchiSet, identifying several limitations, such as the loss of volumetric detail, incomplete window details, and limited editability. 3) We introduce BuildingMesh, a diffusion model specifically designed for generating and editing 3D architectural forms from a single image with customizable window-to-wall ratios, suitable for dynamic architectural design workflows. We propose an regularized method to ensure window consistency. Our framework also includes an interactive module for easy further editing, enhancing platform efficiency and accuracy in professional architectural design workflows. Experimental results demonstrate that BuildingMesh achieves high-quality 3D generation with improved design flexibility and accuracy.