Randy Troppmann

Flash MX2004 has introduced a new tween and easing class (somewhat undocumented) that incorporates Robert Penner’s easing functions. Rumour has it Macromedia hired Robert to implement these. You can see some limited documentation here:

macromedia livedocs entry

This entry does not explain the API. Here is a link to a tutorial:

www.actionscript.org easing tutorial

It can be used simply as this:

mx.transitions.Tween(targetObj,_property,easingEquation,
startPosition,endPosition,duration);

Here is an example:

tween=new Tween(mc,"_x",Strong.easeOut,1,100,150);

For more information regarding Robert Penner’s famous easing equations:

http://www.robertpenner.com/easing/

Thanks to Michael Warf for this link regarding movieclip tweening:
http://laco.wz.cz/tween/