阴天漫射光：最诚实的建筑光线

Create an architectural visualisation lit entirely by an overcast sky, the condition that shows a building most honestly. Show the light as soft and directionless with no cast shadows anywhere, so form is revealed only by the subtle darkening as surfaces turn away from the sky. Detail the sky as a full cloud cover with real tonal variation — brighter overhead, slightly darker at the horizon, with faint structure in the cloud rather than a flat grey. Show the materials reading at their true colour and texture without the flattery of sunlight: the stone's real tone, the concrete's real mottling, the glass reading dark and reflecting the pale sky. Detail the ambient occlusion carefully — the soft darkening in every recess, under every overhang, at every junction — since that is the only shading available. Show the ground as slightly damp with a low sheen. Keep the palette cool and muted with low contrast throughout. Photorealistic, flat soft light, honest and calm, eye-level three-quarter view.