Tweening engines are sets of libraries that make it easy to do animation by code, including all kinds of easing in and out. With only a couple lines of code (or even a single line as we will see), a tweening engine lets you move objects around with smooth transitions. Tweening engines are used widely in 2D Flash applications. Fortunately, they can also be used in combination with libraries such as Papervision3D.
There are many open source tweening engines on the Internet and even more discussions about which one is the best, the fastest, the lightest, or the most convenient to work with. A list of some of the more popular engines is as follows:
gTween: It has some nice features such as smart rotation, rotating objects in the shortest direction, even in 3D. It is developed by Grant Skinner. See http://www.gskinner.com/libraries/gtween/.
TweenLite: It is small in kilobytes and known to be very fast. It is developed by Jack Doyle. See http://blog.greensock.com/tweenliteas3...
