EMAIL: jyrehby@hotmail.com
NAME: Jean-Yves REHBY
TOPIC: Forces of Nature
COPYRIGHT: I SUBMIT TO THE STANDARD RAYTRACING COMPETITION COPYRIGHT.
TITLE: In A Dark Room
COUNTRY: Canada
RENDERER USED: POV-Ray 3.6.1a
TOOLS USED: ArcSoft PhotoStudio
RENDER TIME: about 8.5 hours total (4 h 30 min 44 sec + 4 h 5 min 0 sec)
HARDWARE USED: AMD Athlon XP 2800+, 256 Mb RAM

IMAGE DESCRIPTION:
In a dark room, maybe a dungeon or a basement... The bright sun casts an area of light on the old wooden floor, which suddenly springs to life and grows trees. 


DESCRIPTION OF HOW THIS IMAGE WAS CREATED:
First, about the original idea... I focused on something positive, since I feared that many entries would depict tsunamies, storms, hurricanes and the like. Then I thought about trees sprouting from a wood floor as a surrealist take on the topic. 

Everything was directly coded in POV-Ray's SDL, without any modeller. I created the room from basic CSG, with a granite normal and a slight discoloration at the bottom of the walls to look like moisture marks. The floor has a wood pigment pattern with a home-made colormap, the planks are created with a tweaked brick normal.

I kept the camera perfectly straight, facing the z-positive direction, to preserve the effect of squareness of the room. 

Two light sources illuminate this scene using radiosity: the first one is the sun, and the second one is a white half-sphere stuck outside the window, with no shadow so that the sun can shine through, and a high ambient to actually cast light inside the room.

Two different scattering media are used to achieve the ray of light, both with a bozo pattern. One appears as smoke with only a slight turbulence, while the other simulates some brighter particles. 

Many macros have been written to build trees recursively from branch sections and individual leaves. I took the very opposite approach and defined the whole crown as an isosurface, namely a sphere perturbed by a noise function. I applied a layered texture leaving some holes, so that the limbs or the background would eventually show through at random spots. The limbs are an isosurface based on a noise function. They sure don't look very realistic as such - yet they are mostly hidden and just have to show through random holes in the crown. The trunk is yet another isosurface, this time a cone perturbed by a noise function stretched in the y direction. 

Then, 15 trees of slightly different sizes are randomly rotated around the y axis, loosely aligned on a 3x5 grid, slightly tilted around the z and x axes, and tranlated into place. 

At first I tried to render this scene with high aa settings and both normal and media on for radiosity. It looked like it would take up to 10 days to complete. I then opted for a 2 pass rendering. 
The first pass, with media on, normal off and no aa, at a lower resolution, provides a radiosity file with the right lighting from the sunbeam in the room.
The second pass with media off, normal on, good aa, rendered the final image using radiosity data from the file previously created.
Finally, ArcSoft PhotoStudio was used to convert the pic to .jpg and add my signature.