These graphs are used to illustrate direct sun penetration only at various times of the day on September 21st. This is a simple analysis but can be very useful to consider the potential impact of sun at any time of the year with regards to glare or solar heat gain. Iterative analysis might investigate the incremental benefit of alternate building geometries or fixed architectural shading elements such as overhangs. Areas shaded with yellow represent Illumination values above 3,000 lux (~300 footcandles), generally considered as direct sun.