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Sun Rig #

A sun rig stores directions towards the sun, they are calculated at a location for each point in time in a time pattern using an equation from Michalsky.

Sun rig 3D
A sun rig created with a London location and a time pattern sampling once per hour the 21st of every month.

North Vector#

By default, north is the positive Y-axis. If a model is oriented away from the positive Y-axis then a custom north vector needs to be supplied in order to rotate the sun rig. This vector will be projected to the XY-plane and cannot be on the Z-axis.

Location#

The sun's path across the sky changes depending on the location on earth due to the planet's spherical shape and its tilt in relation to its orbit around the sun.

Sun rig different locations
Three sun rigs at different locations on the earth, London, Singapore and Melbourne.

Time Pattern#

The time pattern contains the points in time at which the direction to the sun will be calculated.

Info

The amount of time steps in the time pattern decides how many sun directions will be calculated per hour and thereby the resolution of any subsequent analysis.

  1. Michalsky, Joseph. (1988). The Astronomical Almanac's algorithm for approximate solar position (1950–2050). Solar Energy. 40. 227-235. 10.1016/0038-092X(88)90045-X.