Exponential keyframes for Z position?


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Exponential keyframes for Z position?
by Kristel Schmidt on Jun 26, 2009 at 9:14:41 pm

Hi everybody,

I came across a situation today where I was animating an object's Z position exponentially (i.e from a value of 40000 to -75 without it jumping in my face in the last second). I ended up just dragging the keyframe handles in the graph editor to smooth out the animation, but was wondering whether any of you knew of a way to have AE automatically create the position keyframes for you. My immediate thought was that you could create a null and give its scale properties the same numeric values as the Z position property, and then either link or duplicate the exponential scaling results. However, copying and pasting different types of data (scale vs position) won't work, so I was wondering whether any of you had any tricks up your sleeve for another workaround.

Thanks in advance!

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Re: Exponential keyframes for Z position?
by Andy George on Jun 26, 2009 at 9:42:54 pm

Hi Kristel,

You could use an expression to create exponential scale along the z axis-

Here is one I found at AEenhancers.com

accellMultiplier=5;

x=position[0];

y=position[1];

z=position[2]+(time-(Math.exp(time*accellMultiplier)));





[x,y,z]

This expression causes your layer to move backwards in z space exponentially over time. accellMultiplier lets you affect when the curve reaches "terminal velocity." If you want to reverse the direction of the push, change the '+' before the parentheses in the z definition to a '-'.

-Andy

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Re: Exponential keyframes for Z position?
by Kristel Schmidt on Jun 26, 2009 at 10:01:04 pm

That's very close to what I was looking for, but I don't think it works in my case as I also have a third Z position keyframe (0) that the object is landing on after going from 40000 to -75.

if I use the script from AEenhancers, the speed from second to third keyframe will be exponentially modified as well, but that's not needed.

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Re: Exponential keyframes for Z position?
by Andy George on Jun 26, 2009 at 10:13:10 pm

Check out this script Ease and Wizz I just stumbled on.

http://ianhaigh.com/easeandwizz/

Types of easing

Regular easing (from most to least dramatic)
Expo, Circ, Quint, Quart, Quad, Sine
Special types
Back, Bounce, Elastic

I have not used it yet myself but
I think it might be just what you need.
Looks very cool-

-Andy

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Re: Exponential keyframes for Z position?
by Kristel Schmidt on Jun 26, 2009 at 11:20:16 pm

Very neat tool - thanks for the tip.

I have a feeling that I may be trying to do exactly what is currently impossible with Ease and Wizz - its "Elastic" effect in conjunction with Curvaceous:

"Note that when you turn on the Curvaceous checkbox, the easing types "Elastic" and "Back" are removed. This is because the expression is unable to extrapolate beyond the end of a curved path (if some mathematical genius wants to figure out how, lemme know)."

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