Annual Solar Irradiation Mapping and Visualization for Complex Geometries

We introduce an innovative approach to producing an- nual solar irradiation data for complex geometries in urban settings. The method uses advanced ray-tracing and ambient sampling approaches with cumulative sky models derived from hourly climate data. In contrast to earlier approaches that have produced annual irradi- ation maps in the form of images from pre-selected viewing points, this method produces results for all the surfaces of the scene simultaneously. In this approach polygon surface meshes are derived from imported building and terrain digital models. Irradiance are calculated at mesh vertices by making use of Radi- ance software tools. This hybrid ray-tracing and statistical sampling analysis allows inter-reflection between and obscuration by other surfaces to be accounted for with high fidelity. The resulting polygon and irradiance data sets are combined to form 3D models for interactive visualization. The method has a number of advantages over existing image-based approaches and is capable of being applied to detailed study of building designs and larger scale urban scenes.