Expression Speed ?

[Dan Ebberts]

If it’s a step change, you could do it like this:

rate1 = 180; // initial rate (degrees per second)
rate2 = 360; // final rate
speedUpTime = 3; // time to start using final rate (seconds)

if (time < speedUpTime){ rate1*time }else{ rate1*speedUpTime + rate2*(time - speedUpTime) } If you need it to ramp up to the new speed it's a little more complicated, but still doable. Dan

[Kevin Mcquade]

Cool, I’ll give it a shot!

And if I did want it too ramp up?
Kev

[Sam Moulton]

i’m so lazy that I’d just add a slider and animate that. Dan’s advanced calculations scare me

[Dan Ebberts]

Something like this should do it:

rate1 = 90; // initial rate (degrees per second)
rate2 = 360; // final rate
rampStart = 3; // start of ramp final rate (seconds)
rampEnd = 5; // end of ramp to final rate

if (time < rampStart){ rate1*time }else if (time < rampEnd){ rate = linear(time,rampStart,rampEnd,rate1,rate2); rate1*rampStart + (rate + rate1)*(time - rampStart)/2 }else{ rate1*rampStart + (rate2 + rate1)*(rampEnd - rampStart)/2 + rate2*(time - rampEnd) } Dan

[Kevin Mcquade]

I tried animating a slider, but nothing happened. I’ll try to use this expression… but I think I too am about to cry.
Kev

[Kevin Mcquade]

Thanks Dan! That expression worked perfectly! Howz about making a layers position change with the beat of a tune? The pick whip puts my object in the corner of the comp!

Kev

[Dan Ebberts]

I’m assuming you’ve just pickwhipped your layer’s position to a keyframed slider created by “Convert Audio to Keyframes”.

To leave the layer in it’s original position and just offset it with the audio, you need to do something like this:

amplitude = 5;
temp = thisComp.layer(“Audio Amplitude”).effect(“Both Channels”)(“Slider”);
value + [temp, temp]*amplitude

Adjust “amplitude” to suit. Here’s another variation that just moves the layer up and down:

amplitude = 5;
temp = thisComp.layer(“Audio Amplitude”).effect(“Both Channels”)(“Slider”);
value – [0, temp]*amplitude

Etc. – you get the idea.

Dan

[Kevin Mcquade]

It just keeps getting better!

Now… not to push my luck here, but what if I wanted the position of the layer to jump all over the place? I used to do it with Motion Math…

[Sam Moulton]

that one I can do…
wiggle(2, 50)

i think the first number is how many times a second, the second is how much. It may be the other way around….