EMAIL: leibnitz@rcn.com

NAME: Edward A. Leibnitz

TOPIC: Journey

COPYRIGHT: I SUBMIT TO THE STANDARD RAYTRACING COMPETITION COPYRIGHT.

TITLE: SolarTransit

COUNTRY: USA

RENDERER USED: POV-Ray 3.5

TOOLS USED: Dave's Targa Animator, avi2mpg

CREATION TIME: less than an hour for all the animation
loops including ad-hoc re-programming of the utility.

HARDWARE USED: Pentium 4 2 GHz 512 M RAM

VIEWING RECOMMENDATIONS: I used RealOne Player - freeware version. 
Any MPEG player will probably work well.

ANIMATION DESCRIPTION:

The Topic is Journey: The act of traveling from one place to the 
other. Going from here to there, with meaning. Your chance to prove 
that it's not the destination that matters, but the journey itself. 

I hope this satifies: I realized recently that renders can benefit 
from shadows that reflect the actual position of the sun rather than 
guesswork (my original method).

THIS ANIMATION IS NOT REALLY "ARTWORK": it is just a demonstration 
of a utility called SolarTransit.inc.

This utility will place the sun "approximately" in the correct 
location given the date, the number of days in the year (i.e., leap 
year or not), time of day (standard am/pm, 24 Hour or elapsed minutes 
of the day) and the latitude. Southern hemisphere latitudes are 
represented as negative values.


Optional information for more sophisticated calculations include:

1] Daylight savings time settings.

2] The location of a city in a time zone (a shift from -30 to 30
   minutes to reflect the location of a city on a specific time 
   zone). 
   
   Sunrise is 4 minutes earlier per degree of longitude East of the 
   imaginary time zone center line.

User's note:

This utility provides an approximation. It will be off (until 
further notice) by certain factors:

1] Issues related to the exact elliptical orbit of the earth around 
   the sun as governed by Kepler's Law, or the heliocentric progression 
   as governed by General Relativity. 
   
   This is very difficult to calculate. It would require astronomical
   data that changes annually. Could be noticably different.

2] Factors not resolvable to within a given day such as the EXACT 
   point of equinoxes and solstices. Most likely a negligible factor.

3] Factors related to infinite plane horizons versus real 
   planetary curved horizons that have slightly different values 
   for sunrises and sunsets. Most likely a negligible factor.
   
4] Factors related to the observed disc-size of the "true" sun ... 
   i.e., in this setting it is rendered as a point-light and not 
   an area light so sunrises and sunsets will be different.
   NOTE: A user can easily change this feature and implement a more 
   sophisticated light source. Could be noticably different.
   
   User's may experiment with disc-shaped light-sources.

5] issues related to an exact longitude are being dis-missed for 
   now. They can involve political issues related to what time 
   zone you are in and whether or not daylight savings time 
   is in effect globally.

Additional note:

Issues related to atmospheric-induced spectrum at a given time-of-day 
that are coded and/or rendered for display purposes are considered 
"test-studies" and DO NOT reflect any serious commitment on the 
part of the developer. These may change at any time. Second-party 
development is openly invited.

DESCRIPTION OF HOW THIS ANIMATION WAS CREATED:

The animation was performed with several animation loops with 
care to keep the endpoints continuous.

1] Place the statement
   #include "SolarTransit.inc" 
   at the top of your code.

2] Place the statement
   TheSun 
   in the appropriate location for your code.

3] goto SolarTransit.inc and set the features needed.

4] Over-ride the default sun point-light if desired.

5] Render.     

User's Note: 

This makes the positive x-axis to be due North.

There are additional code sections in the utility used for 
this competition, such as potential animation loops and 
other #includes that can be removed if desired.

It uses only POV-Ray. The resulting *.tga files were 
converted into an *.avi file using Dave's Targa Animator and 
the end-product mpg was created using avi2mpg.

I am deeply disappointed with the quality of the final 
product in terms of compression artifacts. This looks nothing 
like the individual frames.