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interpolate parameter / adjust rate of change - without keyframes

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Dirk de Jong
interpolate parameter / adjust rate of change - without keyframes
on Sep 26, 2017 at 3:14:20 pm

The Turbulent Noise and Fractal Noise generator effects don't have an option to auto-animate the Evolution at a specific rate (I wish they did). I'm building a comp in which I'd like to be able to simply control the "speed" or rate of interpolation for the Evolution parameter in a single place - probably with an expression control applied to a null at the top of the comp (without having to use keyframes etc.). Is this reasonably possible using expressions ? Thanks for any info and apologies if I'm missing an obvious answer (I did some googling on it and didn't come up with much)


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Dirk de Jong
Re: interpolate parameter / adjust rate of change - without keyframes
on Sep 26, 2017 at 9:14:38 pm

I've only ever used expressions at a basic level but after messing with it a bit it seems that variables don't maintain their values from frame to frame so perhaps even setting a param up to continually increment or decrement (without keyframes) is not currently possible with expressions - so the answer to my earlier question is probably "no."

I wouldn't be disappointed to find out I'm somehow wrong about that though : )

I was halfway thinking I had done this before but now I think I am misremembering it and what I was thinking of is a parameter behavior in Apple Motion called "Rate" which allows for doing this


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Dan Ebberts
Re: interpolate parameter / adjust rate of change - without keyframes
on Sep 26, 2017 at 9:22:10 pm

This may be helpful:

http://motionscript.com/articles/speed-control.html

If you're not discouraged after reading it, come back. ☺


Dan



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Dirk de Jong
Re: interpolate parameter / adjust rate of change - without keyframes
on Sep 26, 2017 at 11:36:42 pm

[Dan Ebberts] "This may be helpful:
http://motionscript.com/articles/speed-control.html"


Very helpful indeed - thanks a lot. For my relatively simple case (of wanting the Noise evolution to progress in a linear way without keyframes with some control over how fast it progresses) simply taking the first expression on the page you referred me to

spd = 360;
value + time*spd

and in the place where the 360 is changing it to point toward my expression control

spd = (thisComp.layer("Null 1").effect("Slider Control")(1));
value + time*spd

basically gives me what I was after - reading the article further and playing around with key framing the speed I see that it gets a little more complicated - but I can definitely work with this - thanks again


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