SunMoon object manages its first child object to simulate the position of the sun or the moon in a given date and a location.
The date is defined using local time. The applied time zone correction is geographical; the computation may include one hour error at certain time zones. The daylight saving time is not considered.
The location is defined by the usual longitude and latitude coordinates. Both coordinates should be given in decimal degree form (not as degrees.minutes.seconds).
To simulate the position of the sun or the moon, the sunmoon object rotates its first child object by its pivot point. This means that the azimuth and altitude angles of the selected target (sun / moon) can be found from the Rotate values of the object space of the first child. The first component, the heading angle, is the azimuth and the second component, the pitching angle, shows the altitude. Zero heading corresponds to the geographic north (= negative z axis of the sunmoon object space).
A sunmoon object can be created using the Sunmoon Tool. Some examples:
Point light sun
|The position of the sun does not matter. However, its distance from the origin should be such that the visual size of the modeled sun appears correct when viewed from the origin. The distance should also be large enough (e.g 1000 times the size of the rest of the scene). Otherwise the position of the sun might change when the camera moves around the scene. However, do not try to use the real astronomical scale; the accuracy of computers is not sufficient for shadow computations from a light source that is millions of kilometers away from the illuminated objects.|
Distant light sun