posted 30 July 2012 21:32            

I want to make a control variable that outputs a log characteristic that would represent an elliptical orbit where one end of the ellipse was 1 and the other -1.

I have thought about using
(!Slope ** (!Gate ramp: !DecayTime s) - 1 / (!Slope - 1))

however I remember some nice math in an example that uses sine and cos for a really smooth rounding of the extremes - I can not find it now... and Math is not my strong point :-(

posted 31 July 2012 14:08            

With a sin wave and it's matching cos wave, they will plot a perfect circle if one is the X axis and the other is the Y. If you change the level of just one of them you will get an elliptical plot instead of a circle.

You can generate a sin and cos with two identical QuadOscillators modules, but feed one with a constant one on the left and zero on the right input and the other with a constant zero on the left and one on the right. Make sure the value/formula in all the Frequency field of the QuadOscillators are the same and then the sin/cos relationship will remain true.

Changing the frequency changes the rate you go round the circle. If you want to go round the circle anti clockwise put in a negative frequency.

Hope this makes sense

Pete

posted 31 July 2012 15:53            

x = a cos(t)
y = b sin(t)

Then I guess you would substitute a fullRamp generator for t. x would be your left-right pan and y would be your front back pan? In your example a = 1, so you can drop that. And b would control the eccentricity of the ellipse.

posted 31 July 2012 19:18            

(x squared / a squared) + (y squared / b squared) = 1

(where a is distance from 0 to the ellipse on one axis and b is the distance on the other axis).

You've already said that a=1, so we can drop it and get

(y squared / b squared) = 1 - x squared

and

y = (1 - x squared)) sqrt * b

So maybe if you put this into a Frequency field:

(1 - !x squared) sqrt * !FreqRange hz + !FreqMin h

you could use it to generate frequencies based on a controller named !X. Note, the frequency would get lower, the larger X is.

Curious to hear.