Hi

I would like to simulate the butterfly flight with its chaotic changes. For this I wrote the following code into the Y Rotation of the left wing (the right one behaves the exact opposite way).

`Freq_Min = thisComp.layer("Prarmètres généraux").effect("Freq_Min")("Curseur") ;`

Freq_Max = thisComp.layer("Prarmètres généraux").effect("Freq_Max")("Curseur") ;

Freq_Offset = Freq_Min ;

Freq_Delta = (Freq_Max - Freq_Min) / 2 ;

Wiggle_Frequency = Freq_Offset + wiggle(1, Freq_Delta) + Freq_Delta ;

//Wiggle_Frequency ;

//Math.sin(10*time*2*Math.PI) ;

Math.sin(Wiggle_Frequency*time*2*Math.PI) ;

When I look the behaviour of this wing through the graphic view I notice that the frequency increases with time whereas I want the frequency to change along the wiggle value.

1 - When I look at the graph of:

`Wiggle_Frequency`

the value oscilates randomly between 8.92 and 10.15

**whereas I expected it to oscilate randomly between 9 and 10**
2 - When I look at the graph of

`Math.sin(10*time*2*Math.PI)`

The frequency (10Hz) doesn't change all along the timeline, everything behaves as expected.

3 - Now if we use this "Wiggle_Frequency" as a changing frequency:

`Math.sin(Wiggle_Frequency*time*2*Math.PI)`

The graph of this third value shows clearly a sinwave which frequency changes but also inexorably increases along time

Whereas

**I expected this frequency not to increase more and more**.

Could someone please spot my mystakes?

I try to find some examples either on creativecow or somewhereelse but I've not found any case like this.

Edit: Here is a screenshot that shows more about this strange behaviour:

in a sin function, when changing the frequency, the changing values are misinterprated by the script so the frequency "goes crazy" without any reason.