An algorithm is described that can be used for computer calculation of the fraction of a window's area that is unshaded by an awning. Awnings with and without sidewalls of arbitrary inclination are included. The case of a horizontal overhang of arbitrary length and width at the top of the window is also included. Equations are given for calculating the effectiveness of awnings in shading windows from diffuse radiation of arbitrary luminance and radiance distributions as well as for isotropic radiation.

Units: Dual