EMAIL: gmccarter@hotmail.com
NAME: Glenn McCarter
TOPIC: Great Engineering Achievements
COPYRIGHT: I SUBMIT TO THE STANDARD RAYTRACING COMPETITION COPYRIGHT.
TITLE: "Dawn Patrol"
COUNTRY: USA
WEBPAGE: http://www.geocities.com/SoHo/Gallery/2006/
RENDERER USED: POV-Ray 3.0
TOOLS USED:
	sPatch (for bezier patch creation)
  Paint Shop Pro (lettering; convert image to JPEG)

RENDER MUSIC: No Doubt "Tragic Kingdom"
RENDER TIME: 7h 38m
HARDWARE USED: Pentium II - 266 mhz

IMAGE DESCRIPTION:

Two millennia ago in east Asia.  It's another warm spring morning.
The Wall remains a mute barrier against the raiders from the north.
Sentries continue to keep a watchful eye into the distance.
But all is quiet.  The barbarians will not come today.

The Great Wall of China was begun during the Qing dynasty, from 221-206 bc.
About 2400km (1500mi) long, it is the longest man made structure in
the world.  This scene shows less than one tenth of one percent of the Wall.


VIEWING THE IMAGE:

This image is stereoscopic -- view it properly, and you will see a striking
three dimensional image.  Here's how: sit a longer-than-usual distance
from your computer monitor.  Don't focus on the monitor; rather, look
THROUGH it with your eyes focused in the far distance.  (Do not "cross"
your eyes.)  Each eye will see two images of the Wall.  Try to adjust
your focus until your right eye sees the right image, and your left eye
sees the left image.  As you do this, these images will merge into one.
The center image will be in stereo.
If you still have difficulty seeing the stereo image, try placing a
vertical, flat divider between your nose and the black bar in the center,
forcing each eye to see only one image.


DESCRIPTION OF HOW THIS IMAGE WAS CREATED:

The scene is 100% raytraced in one pass: no image_maps, no "cut and
paste", no post-processing were used.  So how did I make the stereo
image? It's all done with mirrors.  Instead of seeing the scene
directly, the camera is instead looking at a pair of mirrors, with
a black background behind them.  The mirrors, angled at 45-degrees,
reflect outwards into another pair of mirrors beyond camera view.
These outer mirrors reflect towards the actual scene.

Here's an ascii top view of the setup:


               | |
                | |
               Great
               Wall
                | |
                 | |




        ____________________
          Black Background

  \           \      /           /
   \           \    /           /
    \            \/            /
  Mirror       Mirrors       Mirror


                 o
               Camera



Trace rays from the camera to the Great Wall, bouncing off the
mirrors, and you will see how the image is generated.

I created everything in the scene, specifically for this IRTC image.
The CSG buildings were created directly in the POV-Ray text editor,
but the Wall itself, the guards, the flags, and even the bushes were
made from bezier patches, which were created in sPatch.  I've become
yet another true believer in sPatch, the best tool around for patch
manipulation.

The mountains in the scene are unique: each has it's own heightfield,
scale, colors, and texture.  By careful manipulation of these, various
terrains can be simulated, from nearby rocks and flora to distant hills.
Fog is also used to provide a sense of distance.

The zipfile includes an easy-to-use POV-Ray include file to add
this stereo effect to any POV scene.  But it's not yet complete.
Watch my website for updates...
Try adding this 3D stereo effect to your next rendering.
Then you can view your own Great Engineering Achievement in 3D!