Title: THEORETICAL ANALYSIS OF SKY EXPOSURE CRITERION
Abstract: The purpose of the paper is to analyze theoretically the sky factor with the sky amount as sky exposure criterion, using a three-dimensional spatial model. First, we demonstrate that the sky factor is always greater than the sky amount for any shape of building. Second, we prove that the difference between the sky factor and the sky amount is maximum when the angle of elevation is between 30°and 40°, measured at the center of the building. Finally, we show that the difference is bounded by 11% for any rectangular parallelepiped.