With this iExpression you can connect a property to its own keyframes in an elastic way, as if the property would be connected to its keyframes by a rubber band. This is like the Elastic Connection iExpressions, except that the expression does not follow another property, but its own keyframes.
The iExpression can be applied to 1D,2D or 3D properties and even colors.
Simulation Start Frames
The frame (in composition time), at which the physics simulation is started. Link this value to a slider and keyframe it with a few hold keyframes to restart the simulation at several times. Several shorter simulations compute much faster than one long one. Hence, best start a new simulation whereever the property "takes a break" and does not move. At times where the simulation should not be active, just keyframe the simulation start to some frame after the current frame (say 9999999) to avoid unnecessary calculations.
The softness of the elstic strap. The bigger, the slower and more delayed the object follows the elastic strap.
This is like the friction of the object being pulled by the rubber band. The higher the less it oscillates and the slower it moves.
Max Simulation Frames
For 250 at most the last 250 frames are considered during the simulation, even if the time spans resulting from "Simulation Start Frames" are longer. Setting this parameter to something shorter than the duration of the simulation might cause inaccurate results, but for large numbers, the expression might become very slow.
determines the quality of the physics simulation. The higher this value is the slower is the computation but the more realistic is the movement.