Version 1.6 lets you control the visibility of objects. Objects can be made visible or hidden by putting them on layers, and then turning those layers on or off for each key frame. This allows you to make objects appear or disappear at any point in the animation. The tweens are generated with the same layer visibility properties as the key frames. The animation can then be exported to a movie.
This feature is useful for animating a construction process. The demo below shows how parts are assembled to construct a bookcase. Initially, the parts are hidden. Each part stays hidden until it is required for assembly. Then its visibility is turned on, and it stays visible for the rest of the animation.
The tweens have also been updated to play more nicely with the camera location property. If the keyframe scenes don't save the camera location property, then the tweens won't either. This allows you change the camera location for all of the tweens, on the fly, without having to regenerate the tweens first.