EMAIL: jgrimbert@free.fr
NAME: Grimbert J.
TOPIC: Inventions
COPYRIGHT: I SUBMIT TO THE STANDARD RAYTRACING COMPETITION COPYRIGHT.
TITLE: Planetary gears
COUNTRY: France
WEBPAGE: http://jgrimbert.free.fr/
RENDERER USED: Povray 3.6
TOOLS USED: gentoo ffmpeg toolame festvox
CREATION TIME: about 12 hours of rendering, very short convertion time.
HARDWARE USED: Athlon64 3500+ at 2.2GHz
VIEWING RECOMMENDATIONS: With sound turned on
ANIMATION DESCRIPTION:
The voice is from a text-to-speech web-demo (the text is from me).

DESCRIPTION OF HOW THIS ANIMATION WAS CREATED:
I wanted to make the gear as reallistic as possible: 
the curve of a tooth is very specific.
It turns out that my skill with isosurface were not to the level to make a 3D teeth.
I had the right profile, but filling it was a problem.
Turning back to parametric, I ended with so much artefacts (holes...), 
and it was so long to render that it was irrealist for an animation.
Looking for alternative, it turns out that using two points on the right curve
and the relevant normals,
it was possible to use a circle as a good enough approximation (once you know how 
to place it, of course!). Only if you look very very closely (a view to avoid,
then, in the script of this animation), would you see that two adjacents teeth
are colliding more than hard metal would allow.
Therefor, instead of an isosurface, I returned to CSG.
A shame, because it would make nearly impossible to render an helicoidal gear easily.
Now that the basic element was ready, I had to introduced them on the movie step by step.
Gears computation become a bit heavy at this step (to compute the dimensions,
number of teeths).
Looking at the first 30 seconds, I started to feel it a little boring.
So I then planed to add some sounds to keep the viewer awake, and more important,
explains what's happening.
The first 30 seconds (silent) gives also me a hint about the possible length of
the movie with the encoding parameters (which I do not master so well). I would
probably reach the limit about 70 seconds or so, so I had better have critical
scenes in and forget about any title in the movie.
Moreover, I add to make room for the soundtrack.
More gear-ratio computation later, I had the right speed for each element at each step.
In the meantime, I had also to write the text and get it spoken.
Adjusting each sentence to basically match the time of the scene take a bit of trial
and errors, while the remaining frames were rendered.
First version shown that some colors were badly chosen, and a sign was missing to
hint about the audio.
So, the 40 last seconds scenes get a color-change (and yet another rendering!),
while the first scene was also extended with a text object from the webding font.
(and another rendering of the first 10 seconds! And of course it was not good 
the first time...)