TITLE: Spiders!
NAME: Andrew Spencer
COUNTRY: United States of America
EMAIL: spencere@geocities.com
WEBPAGE: http://fly.to/spencer
TOPIC: Nature
COPYRIGHT: I SUBMIT TO THE STANDARD RAYTRACING COMPETITION COPYRIGHT
JPGFILE: spiders.jpg
ZIPFILE: spiders.zip
RENDERER USED: 
    POV-Ray for Windows v.3.02

TOOLS USED: 
    Paint Shop Pro 4 to create image maps, decrease brightness, add
signature, and convert to jpg.

RENDER TIME: 
    1d 07h 13m 38s

HARDWARE USED: 
    Pentium II 300, 128MB SDRAM


IMAGE DESCRIPTION: 

        The setting is a sparesly wooded oak forest a short walk from a 
lake in Northern New Jersey in early Spring.  A spider has found the 
perfect spot for a web: two thin trees growing very close to each other 
at the base.  Its web is now finished, and upon the center sits the tiny 
creature, waiting for food as the evening begins.  Suddenly, an intruder 
slowly creeps up the web!  The spider turns and stares.  The approaching 
threat is another spider longing for the perfect habitat to steal.  The 
mother spider waits at the center of her web as the attacker continues its 
encroachment.  As a warning she plucks at her web as she does when an 
insect lights upon her strings.  The intruder hangs on persistantly.


DESCRIPTION OF HOW THIS IMAGE WAS CREATED: 

        This entire image was created with pov.  Aside from PSP for the 
image maps and heightfields (all three of them), no external programs were 
used, no pov utilities, no plug-ins or patches or modelers.  This was just
a little goal of my own.
Inspiration-
        What I described in the image description is, in fact, quite true.
I had decided weeks before I knew the topic that this would be my first
submission, and around the same time I had noticed three or four spiders
had made a home out of the window directly beside my computer.  Since they
had no apparent way of getting into my house, I saw no reason to kill them.
Instead, I delighted in watching their daily lives.  The spiders would
come in the early evening, around 5:00PM.  I watched as gnats and small
moths found themselves helplessly trapped and unable to move stuck to the
web and witnessed the spiders' ruthless methods of food preparation.  By
morning they always had disappeared again until just before sunset.
        One night I saw something I found to be especially intriguing.  It
appeared as though one spider was threatening another.  The largest spider
sat passively in the center of her web until another, only slightly smaller,
spider began encroaching upon her.  Once, the intruding even ignored the
warning of plucking and continued moving in, only to be chased out again.
Or maybe they were mating.  I really don't know.
        I now have many videos (taken with my digital cam) on my computer 
of the spider catching, devouring, and preserving her prey.  The spider 
eggs have since hatched, leaving me with dozens of tiny black dots with 
legs (some of which have built their own little webs in my window).  The 
mother, I'm afraid to say, has since died (her legs are still in my window 
and I haven't a clue what happened to the body).
        The location of the image, as described in the image description,
is also very real.  You see my house is on the lake only a short walk from
a sparesly wooded oak forest.  I walked into the forest to find the location
until I found a spider web low to the ground in between two thin trees
growing very close to each other at the base.
The Spiders-
        This was the easiest part of the image.  The spider is a few basic
primitives stuck together to form the basic shape of a spider.  The colors
and patterns on the spider, as well as the orientation of the legs and
size of the spider body parts, are taken from drawings made of none other
than the spiders in my window.  The spiders legs are set up uniformly to
give it the look of rigidity it would have when ready to fight and also
because it made it so much easier.  The second spider is the same as the
first only a bit smaller with the legs moved around so they would land on
the web's rings.
The Web-
        Of all aspects of the image, the piece of which I am most proud is
the web, although I do have to give much of the credit to my father. Before
beginning this image I had no idea whatsoever how to use RAND or WHILE and
had no clue about what sin and cos even stood for, let alone what they
meant.  I first set up the long strands, or spokes, of the web.  Eight of
the spokes are specifically positioned to intersect the feet of the large
spider.  The other seventeen were placed where I thought they looked best.
That part was easy.  Then I went to my father to learn how I could place
cylinders
spiraling outward to get the look of a web.  He explained cos and sin to
me and showed how I could use them to find the ends of the cylinders.  So
my original intention was to find all these points by calculator, write
them on paper, then transfer them by hand to pov.  As I was impatiently
going about this terribly boring business, it occured to me that I had
seen pov to calculations such as these on its own somewhere before.  I still
don't remember where I saw this, but I am extremely glad I did.  I thought
to look through the pov docs.  After doing a search for "cos" I found that
pov could do what I was doing and much more.
        Some weeks before I had written an Email to Sonya Roberts inquiring
as to where I could learn to use RAND and WHILE and such and she sent me to
"The Rendering Times."  There I read a summary of how to use these features,
didn't understand a word of it, and shrugged it off to be learned at a more
convenient time when I had nothing better to do.  However, it occured to me
that this could be the perfect opportunity to learn, so once again I turned
to a more expirienced person for help.  My father read the POVAbilities
editorial and then explained exactly how I could use these options to make
my spider web not only be generated completely by pov, but also use these
new-found commands to make the web more naturally imperfect.  The results
surpassed my expectations.
The Leaves-
        If you are subscribed to the IRTC Mailing List, you may recall I
requested how a single leaf might be modeled.  After reading a few responses
it occured to me to use the image from Sonya's Trees.inc plugin to create
a heightfield.  This rendered a satisfying result.  I then textured the leaf
with random values of red and green (it doesn't look very good up close,
but they are pretty small and out of focus, so that doesn't really matter).
I was originally putting quite a few leaves in and getting oddly sparse
results.  The image wouldn't look satisfactory until I had placed a total
of 3,000 leaves on the ground and 2,000 and the air (for shadow).  This
made the image take FOREVER to render.  Those of you on the IRTC List may
recall my plea for help because my computer wouldn't render it fast enough.
I did get a few with more powerful computers to help me out, but while they
were rendering, I looked at the code for a more fast and efficient means of
placing the leaves.
        Before long I realized I had made a simple mistake.  The leaves
had all been translated randomly and then rotated randomly.  Apparently I
had forgotten that the rotate must always come before the translate...
Upon fixing this, I found 200 leaves on the ground sufficed.  I Emailed
my thanks and apologies to those who were willing to help.
The Rest-
        The camera angle was determined by trial and error, at first I had 
the camera up very close. That however, gave it the look of giant spiders on
a giant web in a giant forest, so in order to preserve the scale, I zoomed
out.  Because of this, I lost many of the spiders' details, but that's life.  
Use of the focul blur was planned from the beginning.  There are three 
light sources: the Sun which is waaaay up in the sky (just like the real 
sun :), and a very dim white light placed on either side of the web to 
create an ambient look without losing the surface normals on the trees.  
The tree bark is a hexagonal pattern (what you can't tell?) of three 
surface normals and three pigments done by eye.  This took a little while 
to get right, but it looks great now doesn't it?  The ground (below the 
leaves) is the same texture as the tree bark, but with a -0.6 ambient 
value to make it darker.  Lastly, the trees are just cylinders sticking 
out of the ground.
        I would like to give a special thanks to those who were willing
to help me out with rendering the old final copy (the one with 5,000
leaves), especially Andrew W. Cherry and Jonas Klereborn for tying up their
computers for two days.  I really appreciate the effort.

