I selected February 3, 2019 to be the day for my light effect. February 3 is Setsubun, the day before the beginning of spring in Japan, The name literally means "seasonal division". I chose this specific date because this house lets the outdoors in; the start of spring is the start of letting the outdoors in after a long winter. Parallels are drawn between Setsubun and New Year’s Eve, so this day is accompanied by a special ritual called mamemicki (bean scattering). As such, I created two containers in the model that contains sesame seeds, which represent beans to scale.
The house is located in Toyokawa, Japan, which has a latitude of 35° N and a longitude of 137° E. Based on the house’s orientation, the sunlight should have an azimuth of 163°. According to the sun calculator, in order to have the lighting effect on February 3 at a latitude of of 35° N and an azimuth of 163°, the effect must occur at 11:10am at an altitude of 36°. When the light hits the north wall at an altitude of 36° at 11:10am, the rays are positioned directly on the slits between the panels. Although this particular lighting effect is not present in the actual house, I incorporated it to emphasize the occasion because at any other time, the same pattern would not occur.