adding randomness to an expression

[Darby Edelen]

[Collin Smith] “My question:
I’m trying to see if there is a way to have the value of the radial wipe transition randomly fluctuate (and preferably control the completion so it doesn’t go all the way back to 0% but rather stay in the upper % range).
Does anybody have any advise or solutions for this?”

The simplest solution might be to use the temporalWiggle(); function on the slider that is controlling the transition.

What this does is wiggle the sampling of the keyframed value by some amount of time. I created a sample video a long time ago to show how this can be useful, the circle has only 2 position keyframes with linear interpolation and an expression applied like:

temporalWiggle(1, framesToTime(5));

In the above case the temporal sampling will vary by up to 5 frames (+ or -) every one second.

Temporal Wiggle

Darby Edelen

[Collin Smith]

Thank You so much Darby.

By the looks of your example video it could work.
Now I just am at a loss on where exactly to place that expression. You mentioned a slider.

As of right now the key frames controlling the transition are set within the Radial Wipe Effect (which is the parent to the other layer with the numeric value I pick whipped). And it’s using this Expression effect(“Radial Wipe”)(1) I attached a screen grab.

Do I add the expression you wrote to this expression or how would I implement it?

random progression to radial wipe

Thanks in advance

[Darby Edelen]

[Collin Smith] “effect(“Radial Wipe”)(1)”

That expression is not really doing anything. It’s telling the property to simply access its keyframed values (which the property does anyway).

Replace that with something like:

temporalWiggle(1, framesToTime(5));

Increase the first parameter to increase the frequency of the wiggle and the second to increase the amount.

Darby Edelen