Adobe After Effects CS4 - Manual (Page 551)

545 USING AFTER EFFECTS CS4
Effects and animation presets
Last updated 12/21/2009
When you create strokes on a layer, the stroke is tied to the location of the current-time indicator in the Timeline panel
when you start drawing. Vector Paint also records the amount of time you take to draw the stroke. For example, you
might start painting a stroke with the current-time indicator set to 0:00 and use 1.5 seconds to draw the stroke. Then,
you might move the current-time indicator to 2:00 and draw a second stroke (leaving 0.5 seconds between the
completion of the first stroke and the beginning of the second one). For this example, let’s say you use 1.0 second to
draw the second stroke. The entire process covers 3.0 seconds on the timeline.
By changing the playback speed, you can change the timing for stroke appearances in previews and rendered
compositions.
1 In the Effect Controls panel under Vector Paint, make sure that Playback Mode is set to Past Strokes, Hold Strokes,
or Animate Strokes.
2 In the Effect Controls panel, click the underlined Playback Speed value and type a new value, using a number in the
range 0–100.
You can also change the playback speed by dragging the value itself or the slider below it: drag left to decrease the speed;
drag right to increase it.
For animations, always begin painting strokes at the layer In point, especially when adjusting Playback Speed. This
workflow locks the In point (start time of the first stroke) to the In point of the layer, making it easier to locate the
beginning of the animation. Then, simply place the In point of the layer where you want the animation to begin in the
composition.
The results that your changes produce depend on the Playback Mode setting:
Animate Strokes With the Playback Speed at 1.0, each stroke appears as if drawn by an unseen hand, taking the same
amount of time as you used to create it. When you increase the Playback Speed value, you reduce the time it takes to
draw each stroke and the gaps between strokes. If you decrease Playback Speed, both the time taken to draw the strokes
and the length of the gaps between strokes increase. Using the example above, if you increase the Playback Speed value
to 2.0 (double the speed), the first stroke would be drawn in 0.75 seconds, the gap between the two strokes would be
shortened to 0.25 seconds, and the second stroke would be drawn in 0.5 seconds. The entire animation would be
complete after 1.5 seconds of playback.
Past Strokes With the Playback Speed at 1.0, each stroke appears in completed form at the frame in which you started
drawing and remains visible for the duration of the layer playtime. When you increase Playback Speed, each stroke
appears at an earlier point in time. If you decrease Playback Speed, strokes occur at later points in time.
Hold Strokes Like Past Strokes mode, each stroke appears in completed form at the frame in which it was drawn.
However, in Hold Strokes mode, each stroke disappears when the next stroke appears (without any gap between
them). Otherwise, the results of changing Playback Speed are similar to the results in Past Strokes mode.
Change playback time with the Vector Paint Re-timer
The results from using the Re-timer or changing the Playback Speed value are similar but have important differences:
• You apply the Re-timer to individual strokes you select before choosing the Re-timer option. In comparison,
changes in Playback Speed apply to all paint strokes on the layer.
• The Re-timer affects only playback that uses Animate Strokes mode. Playback Speed changes can also influence
Hold Strokes and Past Strokes modes.
• The Re-timer does not affect the start times of strokes. Changing the Re-timer value shortens or lengthens the
amount of time previews and rendered versions take to draw the stroke. The strokes begin to appear at the same
points in time as before, but they are drawn more quickly or more slowly.