Hourly beam gate

Method

The direct and circumsolar light are kept when the sun, at the middle of the sunlit part of the timestep, is at or above the skyline, and removed when it is below. The sky diffuse light and the ground-reflected light keep their full value: the skyline takes nothing from them under this option.

The math

$$f_{b,i} = \begin{cases} 1 & \alpha_{m,i} \ge \alpha_{hrz}(\gamma_{m,i}) \\ 0 & \text{otherwise} \end{cases} \tag{1}$$

where

Symbol	Meaning	Unit
$f_{b,i}$	the fraction of the direct and circumsolar light kept at timestep $i$	—
$\alpha_{m,i}$	the sun elevation at the middle of the sunlit part of timestep $i$	degrees
$\alpha_{hrz}(\gamma)$	the skyline elevation in the direction $\gamma$	degrees
$\gamma_{m,i}$	the sun's azimuth at that instant, clockwise from north	degrees

API

options.far_shading_model = hourly_gate, site.use_horizon = true

Symbols follow the symbol registry.