The ExpressionTimeline allows you to apply several expressions to a property such that each expression is active only for a certain period of time. Instead of an abrupt change between the expressions you can also smoothly transition from one expression to the next. Furthermore, you can specify time intervals in which no expression is active such that the keyframed motion is considered.
The script can combine arbitrarily many expressions and works with whatever expressions you give to it.
For the intro scene with TVs on a conveyor belt, generated by two layers of Particular 2.0, I needed a way to smoothly interpolate between straight-line movement and controlled chaos. ExpressionTimeline worked perfectly, merging the two expressions that regulated how the audio was converted into motion. It then helped integrate those expressions with static keyframes for precise control.
I have to say its revolutionary. Seriously. The ability to blend keyframes and expressions, and mixed sets of expression at will can change the way you work forever. And I'm not usually prone to hyperbole.
The user interface
From the beginning until frame 50 use the keyframed values and after frame 50 use a wiggle expression.
Smoothly transition from one expression to another. The first expression is active from frame 0 to 50, the second expression from frame 50 until the end. The smooth transition between the two expressions is 10 frames long and hence lasts from frame 45 to frame 54. With the expressions in this example, the layer first follows another layer (expression 1) until frame 45. Then until frame 54 it smoothly travels back to its own position and simultaneously starts to wiggle (expression 2).
To update ExpressionTimeline download the most current trial version here. Your old installation can simply be replaced. Your installed license is automatically detected and does not need to be entered again.