tween is an actionscript class and can be used after importing the core files. If you’re working with Flash animations and need smooth transitions between property values, the Tween class handles all the interpolation for you. I ran into this when building banner ads that needed rotation and fade effects without timeline keyframes.

The constructor takes the target object, the property to animate, an easing function, start/end values, duration, and whether to use seconds or frames. You can chain multiple tweens on different properties to get complex animations. The easing classes like Elastic, Bounce, and Regular give you different motion curves out of the box.

import mx.transitions.Tween;
import mx.transitions.easing.*;
//Tween( obj:Object, prop:String, func:Function, begin:Number, finish:Number, duration:Number, useSeconds:Boolean);

e.g.

Earlier post on ActionScript goes deeper.

var myRot:Tween = new Tween(myText, "_rotation", Elastic.easeOut, 0, 360, 3, true);