Apple Motion 5.1.1 - Manual (Page 897)

Chapter 20 Shapes, masks, and paint strokes 897
The following example demonstrates how to use a mask to isolate an object in a clip in order to
apply separate effects to the isolated object and its background.
Original image
Masked image
Composited image (Mask allows
different effects to be applied to
the background image and the
foreground image.)
Rotoscope a subject by animating a mask
1 Choose View > Resolution > Full to ensure that you are viewing the Canvas at full resolution.
Important: If the Canvas resolution is not set to full, the outlines of objects and images may
shift slightly. As a result, masks created to trace a subject at less than full resolution may not
be accurate.
2 Move to the first frame where the mask animation should begin, then draw a mask that
accurately isolates the subject.
3 When you’re finished drawing the first mask, click the Record button in the transport controls (or
press A).
Active Record button
4 Move to the first frame of the Timeline where you want to change the shape of the mask, then
make any necessary changes to its control points.
67% resize factor