5

The Reduce Keyframes dialog appears.
Reduce Keyframes applies a thinning algorithm to the keyframes for the parameter. This
reduces the number of keyframes while attempting to maintain a similar shape to the
curve. The thinning algorithm can be adjusted in two ways. Increasing the Error Tolerance
results in fewer keyframes. Increasing the Smoothing (frames) makes smoother curves
between keyframe values.
This example uses 5, which means that 5 track points centered on the evaluated point
are used to compute the current point’s new, smoothed value. This is a standard Gaussian
(bell-curve type) filter. In other words, if you leave the Smoothing value at 5, when the
value of frame 12 is computed, frames 10, 11, 12, 13, and 14 are considered. If Smoothing
is set to 3, the algorithm uses frames 11, 12, and 13. The larger the Smoothing value, the
more points are considered (and thus more calculations done) for every point in the
curve.
2 Set the values in the Reduce Keyframes dialog.
As you adjust the sliders or value sliders in the dialog, the curve is modified in the Keyframe
Editor. There are now fewer keyframes on the curve, and the curve becomes smoother.
3 Click OK.
Averaging a Track Curve
Another smoothing option is to apply the Average parameter behavior to a track curve
in the Keyframe Editor. This behavior smoothes the transition from one keyframe value
to another. Averaged motion moves more fluidly.
To apply an Average parameter behavior to a track curve
µ
In the parameter list of the Keyframe Editor, control-click the parameter name, then
choose Average from the shortcut menu.
1328 Chapter 22 Motion Tracking