Exponential Curve Expression

[Jon Smith]

Just wanted to add that the error I receive is:

Bad method arguments: second argument to div() must be a scalar

And also Is there a way to add easing to these moves?

Thanks again

[Filip Vandueren]

I usually do exponential scaling with a slider:

add a expression slider-control to your layer and rename the slider to “Z”

Give the layer’s scale this expression:


exp = effect("Z")("Slider");
Math.pow(1.01,exp) * value;


Positive values for the slider => bigger, negative => smaller.
The nice thing about this is that you can ease the keyframes on that slider. Or even add an expression to it etc. (I usually add a smooth).
you can also still use the scale of the value if you need to flip or disproportiantely scale the layer because it get’s mulitplied in.

If you want the 2D-position to also fake perspective (smaller= nearer to the vanishing point), add this expression to position:


exp = effect("Z")("Slider");

compCenter=[thisComp.width,thisComp.height]/2;

compCenter + Math.pow(1.01,exp) * (value-compCenter);


Note: if your layers are parented, stuff get’s more complicated, so this will probably not look okay then.

[Selim Mete]

Hi Filip,

In my AE project, I have a counter that needs to speed up exponentially as it counts down.
The numbers are going down from 30 so I can do this manually by creating keyframes but I’d rather learn from this experience and do it using expressions.

Do you think your solution can be applied to my case?
I’m a newbie in AE programming so hopefully my question isn’t too simple or obvious.

Thanks,

Selim

[Kalleheikki Kannisto]

Since you have exact beginning and end values, it is easier to do this with a slider and use either keyframe assistant or the graph editor to make it exponential.

[Selim Mete]

Hi Kalle,
Thanks for your quick response.
I know pretty much nothing about AE expressions thus haven’t used a slider to modify text values. The problem is I don’t even know what to search for to find a tutorial that can help me with this.
Do you have any recommendations?
I’d also be happy to hire your services (or buy you a beer if it’s something super quick) to teach me how to do this 🙂
In the meantime I’ll keep watching some tutorials and see if I can figure it out.

[Kalleheikki Kannisto]

It’s pretty straightforward:

– Add a slider to a layer, animate it from 30 to 0 with two keyframes

– Pickwhip the slider to the source text expression of your text layer. You’ll probably want to round the value to integers, for which you can use the round expression Math.round(pick-whipped-value-here)

then either

a) Select the two keyframes for the slider value, right click and select keyframe assistant > exponential

or, for more detailed control

b) click on the “show in graph editor” button for the slider value and switch to the graph editor and adjust the curve to be exponential

[Selim Mete]

Thanks so much! Worked like a charm.

The only thing was that Math.round rounds it down at .5 which I worked around by entering beginning value as 30.5 instead of 30 (I’m sure there is a math function to do this as well), then with the right line graph all the other seconds lined up perfectly until the point where I intentionally was able to do the “speed ramp” and speed up the countdown exponentially, this time using a curve.