TITLE: Black Magic
NAME: Guillermo Sanz Romero
EMAIL: famrom@ran.es
WEBPAGE: http://www.geocities.com/SiliconValley/4774/index.html
TOPIC: Magic
COPYRIGHT: I SUBMIT TO THE STANDARD RAYTRACING COMPETITION COPYRIGHT.
JPGFILE: gr-black.jpg
ZIPFILE: gr-black.zip
RENDERER USED: 
    POVRay 3.01.msdos.wat-cwa

TOOLS USED: 
    DOS Edit and Micrografx Picture Publisher 5.0 & 7.0

RENDER TIME: 
    28h 13m 18s (21h 24m 45s + 6h 48m 33s)

HARDWARE USED: 
    PC iP55-166MHz(MMX)


IMAGE DESCRIPTION: 


Jervis, the Rotten, a great demonologist needs to contact Urgh-Nak-Orlep,
the Lord of 7th Hell, the Master of Fire, the Green Flame, the One Who Glows
(these names are public ones, the real is secret, of course).
After carving the pentagram in the ground, he casts the ancient spell.
A dimensional gate opens, while the pentagram protects the magician.
In the moment Jervis says the secret name, the Demon appears.
He is not happy, demons do not like to be disturbed. If He would be able to
cross the magic symbol He will eat the magician's soul, and then go back
to His dimension...


DESCRIPTION OF HOW THIS IMAGE WAS CREATED: 


The first idea for this scene involved a triangle mesh. I want to have a demon
with a cow/goat head, and a body made of halos or something like that. I asked
a friend if I can go to his office and use their LW5 to get the head. After
returning home with the head in a floppy, due to problems with the format
converter, I was unable to use that mesh. Argh! =: 

So, I tried a different view point: the Demon will be only halos, maybe some
primitives. With this in mind, I started with the candles (I did no like to
work more in the Demon after a full afternoon of frustration). The candle
is build with some cylinders and a torus for the basic shape. Then I wanted
to get drops of wax along the sides, but I do not wanted to use a 3th party
inc file. The solution, some loops and a lot of "rand"s to generate the wax
(a blob, cylinders for the big parts, spheres for the tips and pools).

For the flame, I examined other people work, and the only idea that convinced
me and I used was that the Piriform was the ideal primitive. After some "try
& error", I managed to get the desired effect. Two piriforms, and four halos
was enough. Each piriform has two halos, one cylindrical and one spherical.
Two piriform, one inside the other, and with different tilt, gives the effect
of a live flame: bright inside and bottom, semi transparent sides and top.

Next thing was the ground, I used Picture Publisher 5 to paint a GIF. The
initial draw was a square reticle, but using a lot of filters and the paint
tool I finally get a 6*6 tiles of stone, some cracked, some erosioned, none
equal to another. This GIF was place 9 times over a plane to make the ground.
Every copy of the heightfield has been rotated or scaled (scale -1 = mirror)
so there is harder to realize the tiles repeat in some parts. =: 

The texture for the height field is simple, a color, because all the detail is
in the GIF (no normal {} needed). The plane texture is a mix of sand and moss,
the effect of moss or sand is obtained with normal statement, nothing more. In
the final render, this plane appears really dark, so the effect is even less
important (but I like to build all as the more precise I can).

The pentagram is one of the heighfield minus a torus and five cylinders. I
wanted a rare symbol, not just a painted one, so the idea of carved stone was
attractive (magically carved, of course). In every tip I placed five candles,
every candle is generated with the inc file randomly (5 candles/tip, a five
tips star = 25 candles).

The magical fire that is forming in the pentagram is an halo, built inside
a copy of the symbol. It uses planar mapping, and if you look from the top,
nothing can be seen, it is visible only from the sides (funny :  ).

The wall is another plane, and the texture come from one of my inc files (I
am trying to develop inc files to build Dark Age/Fantastic houses). The timber
are superellipsoids, because boxes are too perfect. The texture is, IMO, the
only thing I have used but do not made; it is the POVRay teak map, with a
woodgrain from woods.inc.

Then I started the light tests. In every flame there is one light, and to
simulate as better as I can a candle, the color is dim yellow, and with fade
distance very short (25 independent lights, argh! :-/ ). The scene looked
dark, the way I expected.

The dimensional gate is a disc and a cone. The disc texture is a transition
from dark to cyan then pure white, ending clear. Every color has different
transmit and normal values, so the background can be seen, but distorted (when
there is no Demon). The cone texture is a spiral, with the caps transparent
(gradient clear-spiral-clear). This two things, make a gate as I imagine them,
bright, a bit transparent and distorting the background.

The Demon is an green halo for the head (does that be a head?). The eyes are
two piriforms (yes, I like this shape, the question is why I need so much time
to know it?) and two clear spheres with red halo. This part of the scene
involved a lot of tests (using the commands to render parts of the image),
because controlling halos is hard. When I got the shapes I want, I noticed
that the Demon was bright, but It did not emit light.

The candles' result was so good, I decided that all lights should use fade
distance. One blueish in the gate, one green in the monster cloud, and one in
each eye. No area lights, but the final illumination, IMO, is smooth.

The candle took me one day, the room two (including the GIF), the gate and the
Demon near two more. The final image is not photorealistic, but I think the
result is also interesting, because it looks like a draw (you know, one of
those used in fantasy books and comics, like Lord of the Rings).

The scene was rendered three times: no radiosity (over 7h), fast (over 12h)
and normal (the one I submit, over 28h). This is because I had enough time
(the only submission I have ended with time to spare), after all, it is
summer time. d8- 

The image was converted from PNG to JPG with PP7. The signature was added with
this program too.  I have PP5 for Win3.1 and PP7 for NT, I work normally in
DOS, but the PP7 JPEG export is really good (you know the size before
converting, due to the auto-preview) .

NOTES:
For small resolutions, "smooth"ing heightfield is unnecesary, maybe in
bigger images (the GIF is 900*900 pixels).
The candle and brick inc files are experimental, I will release a full
corrected version as soon as posible (and with docs).