GreenSock Docs (HTML5/JS)

PhysicsPropsPlugin

Sometimes it's useful to tween a value at a particular velocity and/or acceleration without a specific end value in mind. PhysicsPropsPlugin allows you to tween any numeric property of anyobject based on these concepts. Keep in mind that any easing equation you define for your tween will be completely ignored for these properties. Instead, the physics parameters will determine the movement/easing. These parameters, by the way, are not intended to be dynamically updateable, but one unique convenience is that everything is reverseable. So if you create several physics-based tweens, for example, and throw them into a TimelineLite, you could simply call reverse() on the timeline to watch the objects retrace their steps right back to the beginning. Here are the parameters you can define (note that friction and acceleration are both completely optional):

  • velocity : Number - the initial velocity of the object measured in units per second (or for tweens where useFrames is true, it would be measured per frame). (Default: 0)
  • acceleration : Number - the amount of acceleration applied to the object, measured in units per second (or for tweens where useFrames is true, it would be measured per frame). (Default: 0)
  • friction : Number - a value between 0 and 1 where 0 is no friction, 0.08 is a small amount of friction, and 1 will completely prevent any movement. This is not meant to be precise or scientific in any way, but it serves as an easy way to apply a friction-like physics effect to your tween. Generally it is best to experiment with this number a bit, starting at a very low value like 0.02. Also note that friction requires more processing than physics tweens without any friction. (Default: 0)

USAGE:

TweenLite.to(mc, 2, {physicsProps:{
x:{velocity:100, acceleration:200},
y:{velocity:-200, friction:0.1}
}
});

PhysicsPropsPlugin is a Club GreenSock membership benefit. You must have a valid membership to use this class without violating the terms of use. Visit http://www.greensock.com/club/ to sign up or get more details.

Copyright 2017, GreenSock. All rights reserved. This work is subject to theterms of useor for Club GreenSock members, the software agreement that was issued with the membership.

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Version: 2.0.1 updated 2018-05-30

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