Bezier warp expression - slowing amplitude and velocity with fast decay

Question

I've been working with an expression from Dan Ebberts Vibrating strings which I have modified to create a bending effect on a solid shape
This part is applied to a slider expression of the solid
veloc = 14;
amplitude = -250;
decay = 4;
amplitude*Math.sin(veloc*time)/Math.exp(decay*time)
Then a bezier warp has been applied to the solid shape to the Bottom Right Tangent and Bottom Left Tangent
value + [0,effect("Slider Control").param("Slider")]
This works very well except that I would like to be able to have the amplitude of the bending shape slow down as it bends and then snap back quickly in the decay but  I'm not sure how to accomplish this.  I have tried playing with the settings that I have, but am unable to make this work.
Any help would be very much appreciated.
Ira

Answer 1

I'm not sure what you're describing exactly. The expression you're using generates a damped sine wave. What would the new waveform look like? Would it be the same except eased so the the wave spends more time close to the extremes and less time transitioning, or something else entirely?
You could build your own, triple-eased periodic waveform like this, but I'm not sure it's what you're after:
veloc = 14;
amplitude = -250;
decay = 4;
period = (Math.PI*2)/veloc;
t = (time+period/4)%period;
if (t < period/2)
  v = ease(t,0,period/2,-1,1)
else
  v = ease(t,period/2,period,1,-1);
v = ease(v,-1,1,-1,1);
v = ease(v,-1,1,-1,1);
amplitude*v/Math.exp(decay*time)
Dan