Apple Motion 4 User Manual
Page 1114
Random Start Frame:
A checkbox that introduces variation to image brush strokes using
multi-frame source objects. If the checkbox is selected, each dab will pull from a random
frame in the source. The dab will either start animating from this random frame or remain
still depending on whether the Play Frames checkbox is selected or deselected. This
pattern of randomness can be adjusted by using the Random Seed button under the
Stroke Pane.
Source Start Frame:
Click the Source Start Frame disclosure triangle to display a mini-curve
editor that allows you to define the frame at which playback of the source clip begins in
the paint dabs. The Source Start Frame default keyframe value is 0, at which playback
starts from frame 1. You can simply change the start frame for all dabs, or you can create
a curve so that start frames vary over the length of the stroke (different dabs use different
start frames). For example, if the first Source Start Frame value is 50, each dab begins
playback at frame 50. If you create an animation curve that begins at 50 and ends at 250,
each dab begins clip playback at a progressively later frame.
The Play Frames checkbox must be selected in order for playback to occur. If Play Frames
is deselected, you can display different still frames over the length of the stroke. This
parameter only appears if Random Start Frame is deselected.
Note: For information on using the mini-curve editor, see
When you click the Source Start Frame disclosure triangle, the Stroke Length and Source
Start Frame parameters become available.
• Source Start: Use the sliders or enter a number into the value field to change the value
of the selected keyframe in the mini-curve editor.
• Stroke Length: Stroke Length is mapped horizontally on the mini-curve editor graph
and provides a visual representation of the position of the changes in start frame value
(keyframes) over the length of the stroke. Use the sliders or enter a number into the
value field to change the value of the selected keyframe.
Hold Frames:
Sets the number of times each frame of the source movie is repeated
during playback. The larger the Hold Frames value, the slower your playback.
Hold Frames Randomness:
Varies the number of frames to “hold.”
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Chapter 17
Using Shapes, Masks, and Paint Strokes