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Activity Forums Adobe After Effects Expressions Animating A mouse’s tail using expression

  • Animating A mouse’s tail using expression

    Posted by Adam Ben ami on December 27, 2011 at 11:49 am

    hi,
    i bet i can find some help here, you guys rule!

    anyway.
    i got a mouse and a tail. the tail is broken to segments.
    i want to move the mouse and it will auto-orient the body. and the tail will get the rotation from the direction and velocity of the body.

    i manged to get a good movement on the tail with parenting and valueAtTime + offset time on each layer
    now my problem is how to get a the rotation from the body to the tail’s root
    ,
    i tried to use an expression to auto-orient the body and by that to get a rotation value, but that just curls up the tail.

    any suggestions ?
    i think this is a hard one..

    Nate Vander plas replied 14 years, 4 months ago 3 Members · 4 Replies
  • 4 Replies
  • Dan Ebberts

    December 27, 2011 at 2:55 pm

    I would think you could just make the tail a child of the body and add a wiggle expression to the tail’s rotation property.

    Dan

  • Nate Vander plas

    December 27, 2011 at 5:16 pm

    I have a similar problem, but a wiggle expression will not work. Mine is a plant (a long stem with leaves on it) which someone is holding. I have their hand tracked, so I have the position and rotation to make the plant look like it’s in their hand. What I’d like is to have the plant bend and sway in a natural, springy way as he moves/rotates his hand. I have the plant as one layer with 5 puppet pins along the stem. I then have 5 nulls that the puppet pins are each linked to with expressions. I’ve found that if I use a delay expression on each subsequent null going up the plant, it can have a nice wave effect. This is with the top parented to the next one down, and so on. But what I need is the rotation for the first null. I could hand-animate it, but it’s time consuming and I have 10 of these to do.

    Suggestions?

  • Dan Ebberts

    December 27, 2011 at 6:23 pm

    I think it’s possible, but complicated. You’d have to calculate the velocity vector of the attach point at each frame and sum up the decaying effect of each “impulse” for some amount of time into the past. Then you would translate that to angular motion. I’ve done something similar to simulate the rocking action of a car that occurs when you accelerate or put on the brakes. Do-able, but hard to describe and probably not worth it unless you have to do a bunch of them.

    Dan

  • Nate Vander plas

    December 27, 2011 at 6:41 pm

    Yeah, sounds awfully complicated. Guess I’ll just hand-animate.

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