Here comes the sun

Craig Berry cberry at
Tue Jul 10 17:17:34 PDT 2007

I'm driving myself nuts trying to work out the mathematical model that
drives sun position in SL.  I've built  a "solar observatory" that
gathers data and pumps it out to a web server.  From analyzing that
data, I've concluded that the "year" is 11 SL days (44 wall-clock
hours) long.  There are "seasons" of a sort, but as the Wiki article
on llGetSunDirection notes, things aren't consistent with a planet
moving in a rough circle around a star.  Instead, there's some kind of
combined tilt plus offset (on both local y and z) at work, and both
seem to vary over time.  Even the angular rate of the sun at noon
varies from day to day over the course of a "year".  There are too
many free variables for me to figure out what geometric (or purely
mathematical) model might fit all this.

Has anyone else explored this area, beyond the cursory note in the
Wiki?  I'd hate to think I'm duplicating effort.

Craig Berry -
"The road of excess leads to the palace of wisdom." - William Blake

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