In this study, the solar energy gain on 3-D geometries and the amounts of energy output from photovoltaic panels fixed on selected geometries were determined using the radiation data collected by the Iranian Meteorological Organization on a horizontal surface. The results can be used in designing solar houses, street and traffic lights, and rail transport systems. The K-T model was used to calculate the daily average solar radiation intensity; the solar radiation data on a horizontal surface in Kerman was used as input in the above mentioned model. The solar energy on 3-D geometries was calculated in different directions throughout the year. Finally, the geometries were compared with each other in terms of solar energy gain in different months of the year. The results show that the solar energy gain on selected geometries in hot season of the year prevails in east-west direction. (C) 2013 Elsevier B.V. All rights reserved.