time*(slider value) trouble

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jmricks
Posts: 1
Joined: May 24th, 2009, 8:26 pm

I'm trying to parent the Y value of the Tile Center of a Motion Tile effect to a slider so it is constantly moving and I can easily change the speed of the movement with the slider.

Right now I have it set up like this:

Code: Select all

x=effect("Motion Tile")("Tile Center")[0];
y=time*effect("speed")("Slider");
[x,y];
It works fine if the speed is constant throughout the comp, but if I want to change the speed it doesn't work as I would like it to.

If on one frame the Slider is set to 350, and a few frames later it changes to 375... instead of making the movement gradually speed up and keep moving at that speed, it speeds up a lot while it changes to 375, and then slows down.

I understand why this is happening because 12.5*350=4375 while 12.5*375=4687.5. So when the slider changes it suddenly jumps to a much larger number. But 12.6*375=4725 so it slows back down after it reaches the keyframe I set in the slider.

So what I get is a rapid speed change faster as the slider animates, and then it slows back down after the slider reaches the new value at the next keyframe. What would I need to do to basically get the motion tile moving at say 5 pixels/sec, then move the slider to a new number and get the motion tile moving at say 10 pixels/sec, without the drastic speed up/slow down?
kobyg
Posts: 128
Joined: December 7th, 2007, 10:11 am

Checkout this post, I think this is what you wanted:
http://www.aenhancers.com/viewtopic.php?f=6&t=1302
Koby.

p.s.: What is called there "acceeration" is actualy the "speed" you were referring.
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