GeoSun 1.1.1 for Maya (maya script)

Adds geographical location, time and date features to the physical sky in mentalray and calculates daylight angle.

Replaces the faulty sun position calculation algorythm of SunLight v1.0 with a precise calculation, including annual changes of the ecliptical plane and athmospheric refraction. (Source for algorythm: https://de.wikipedia.org/wiki/Sonnenstand),

Adds support for z-Up systems and integrates it into the Mental Ray Physical Sun.

Site for geographical Co-Ordinates: https://www.bcca.org/misc/qiblih/latlong.html
OR use GoogleEarth.


Files:
geoSun1.1.1.mel ->the script
userSetup.mel -> sample file for autoload at maya startup (see below)
converter co-ordinates.xls -> excel sheet with a converter from degree to decimal coordinates

Usage comments:
- All coordinates in decimal degrees, North/East positive, South/West values negative.
(use the excel file included to convert standard degree-minute-second co-ordinates as used in google earth)
- Use "useHourValue" to animate daydime (decimal hours instead of hours:mins)
- Use "useDayValue" to animate the date (fload value for julian day instead of day/month)
- effective daytime and date actually used for the calculation are displayed in the attribute window.

Author: Nils-Peter Fischer (Nils-Peter.Fischer@web.de)
UI Based on SunLight v1.0 by Miguel Kabantsov (miguelkab@gmail.com)

Date of creation: 07-05-07
Last change: 08-04-25


Version 1.1.1 installation

to ensure all scenes open smoothly once a light with geoSun-links has been created, the procedures have to be loaded upon Maya startup:

1. create a file "userSetup.mel" in your userhome/Documents/maya2008-x64/scripts folder or edit it if existing.

2. add a line
source "geoSun1.1.1.mel" ;
to the file.

3. copy geoSun1.1.1.mel into the directory above.


Now all procedures necessary to calculate the sun position are available after maya started and a file opened with a geoSun object will work without manually sourcing the script.

Version 1.1.1 usage

1. Create a MR physical sun
2. exectute geoSun() either in the command line input or through a shelf button
3. select the sunShape node in the outliner
4. open the attribute editor and expand "Extra Attributes" where all sun parameters can be accessed



Important: if you delete the sun node and wish to re-create a new geoSun, use the "delete physical sky" button in the MR render prefs first. Otherwise geoSun assumes an already existing setup and will return an error message. Only one geoSun system can exist in a scene.


Version 1.1.1 network rendering
to use geoSun for network / batch rendering, user the -preFrame or -preRender command to load the script before execution of each frame.