The heliodon is designed to create a sun. With the heliodon you set the latitude and longitude (or you select the city) then set the day and time. Vectorworks will then calculate the correct angle of the sun. You can edit the time of day by typing in the time, or you can type in names like “dawn”, “sunset”, etc. But you can do more than just setting the sun position; the heliodon is also used to create solar animations, which can show the way the sun changes during the day and the way the sun changes over the seasons.