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Trying to find Inverse Function — Please Help!
Hi there,
OK I banged my head against this for quite a while but I can’t figure out how to do it:
I have a curve expression and I am trying to create a second curve that is the inverse of the other — that is, what the curve would be if reflected in the axis of y=x.
The curves in question take their beginning and ending values (which can range between 0 and 100) from other expression controls in the same layer, and interpolate using a linear “Progress” value which is keyframed from 0 to 1.
They are also adjusted in turn so that they each range from 0 to 1 (because I’ll be using them elsewhere as interpolation curves for further parameters).
Right now, the Expression Control called “Exponential Progress” curves correctly; but the one below it called “Inv. Exponential Progress” has a curve which is a vertical reflection of the former, like what an “ease out” looks like compared to an “ease in”. This is wrong. It should look like the reflection in y=x.
I really hope one of the math wizards here can solve this one……!!
Project included here, in CS4 format
Lu Nelson
Berlin, Germany
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[MacProQ2.66, 8GB, Sys10.5.6, FCP 6.0.5, AE 9.0.2] -
3 Replies
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I think you’d just flip x and y. So if the value is in a variable named ‘result’, it would just be [result[1],result[0]].
dan
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Ah — I was just responding to your other post
Yeah I wish I could see how to do that; but if you look at the project you’ll see the data isn’t vector it’s scalar. These curves aren’t animation (spatial) curves they’re value curves, which I want to use for driving interpolations down the line.
The question is to determine the inverse function, where you’ve got y=f(x), and determine a new equation for y that gives the inverse function…unless I’m missing something obvious?
Lu Nelson
Berlin, Germany
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[MacProQ2.66, 8GB, Sys10.5.6, FCP 6.0.5, AE 9.0.2] -
Well, I looked at using some other curves and their inverses, which were easier to calculate, and it looks like the opposed curve that I had already found in my example above does the trick for what I need better than an inverse would, so I’ll call this one off…
Thanks for the views and thoughts though
LMN
Lu Nelson
Berlin, Germany
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[MacProQ2.66, 8GB, Sys10.5.6, FCP 6.0.5, AE 9.0.2]
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