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view demo :: http://the.fontvir.us/pv3d/PQtorus/
view sources:: http://the.fontvir.us/pv3d/PQtorus/srcview/
view blog post :: http://the.fontvir.us/b10g/?id=116

here we go again, another papervision3D demo featuring math permeated lines.
this time im working with a classic piece of code known as the PQ torus. the vague
idea is that you have 2 numbers (P + Q) that are used in the algorithm to define the
knot. in general, given P + Q mutually prime, the line wraps meridionally around the
torus P times and wraps the longitudinally around it Q times. i was having some
trouble grasping exactly how this was going to be achieved, until i read this article
on blackpawn’s website. he really breaks down the algo to a very simplistic level...

r = .5 * (2 + sin(Q * Φ))
x = r * cos(P * Φ)
y = r * cos(Q * Φ)
z = r * sin(P * Φ)

simple right? lol.
so Φ (or phi in my code) is basically a variable that is definded by change.
in this case, im simply incrementing phi + .02 every frame. this seeds the
math and gives you the cool visual effect.

anyway, after getting a handle on the math, writing the demo code was a snap.
i took the existing code i wrote from the 3D object tracer and the lorenz attractor
and combined them. (i also found + fixed an error for computing the line gradient
color) i started out by allowing the users to only select values for PQ and that
actually made sense.


but after some experimentation i found that using some unorthodox values
for P+Q could net some very interesting results. take a look at some of these...




e n j o y !

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Hello,
Waooow ! It's very nice. It works perfectly ! Bravo !

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Minneapolis

Nice work. I listened to Firestorm's IK+ remix and Ooh La La by Slyspy while playing with this. Amazing stuff, matched the music rather nicely. (hint, Demovibes 9)

One thought- make one where as it draws it fades the older lines, so what you can constantly have glowing particles whipping around the camera when it's zoomed in. It would look really cool.

Last edited by arfink (Feb 4, 2010 8:12 pm)

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arfink wrote:

One thought- make one where as it draws it fades the older lines, so what you can constantly have glowing particles whipping around the camera when it's zoomed in. It would look really cool.

agreed,
good idea, i will experiment with that

thanx!