Methods and systems for real-time visualization of building structures are disclosed. A computing system may calculate physical illumination characteristics for each of a plurality of predefined virtual external building-surface elements layered in simulation at specified surface locations of a virtual three-dimensional (3D) model of a building structure, wherein the virtual 3D model is constructed based on data descriptive of the building structure. Each of the plurality of predefined virtual external building-surface elements may be associated with its calculated illumination characteristics in a database. A spatially-manipulable rendered image of the building structure may displayed on an interactive display in real-time based on the virtual 3D model. On the interactive display device, one or more of the plurality of the predefined virtual external building-surface elements may be rendered in real-time at respectively specified locations on the rendered image. On the interactive display device, illumination of each of the one or more of the plurality of the predefined virtual external building-surface elements may be simulated in real-time based on its associated calculated illumination characteristics, its respectively specified location on the rendered image, and a specification of environmental illumination conditions.