Apple Motion 4 - Manual (Page 1064)

About Shapes, Masks, and Paint Strokes
Shapes and masks are vector-based objects that are drawn and edited using control
points that define mathematical curves. Each control point in a shape defines some sort
of corner or curve, and the actual spline that makes up the shape connects these control
points together like a connect-the-dots drawing. You can edit or animate any shape by
moving and editing its control points or by applying a Shape behavior.
Shape behaviors are designed specifically to be applied to shapes and masks, and perform
tasks such as oscillating the position of the control points, tracking the control points,
writing on a shape over time, as well as randomizing or wriggling the position of the
control points. As with all objects in Motion, you can also apply Basic Motion, Parameter,
and Simulation behaviors to shapes.
A paint stroke is a shape that is created in one of two ways: You can “paint” the stroke in
the Canvas using the Paint Stroke tool in the Toolbar, or you can modify the outline of
an existing shape. The Paint Stroke tool allows you to use a stylus and graphics tablet (or
a mouse) to create a paint stroke, rather than drawing the shape in a point-by-point
fashion (like a Bezier or B-Spline shape). In addition to sharing other shape outline
parameters, paint strokes have a unique tool set that allows you to change the look of
the paintbrush and to create particle-type effects with the stroke. Paint strokes have a
special behavior called Sequence Paint, which allows you to sequence the stroke
parameters over time, such an opacity, rotation, and scale.
The Paint Stroke feature is a design and graphics tool, not a retouching or rotoscoping
tool.
Note: Using a stylus and graphics tablet is recommended when using the paint feature.
While you can create paint strokes using the mouse, a pen allows for a more fluid creation
of strokes.
Because shapes are mathematically defined, you can take advantage of the vector nature
of shapes to resize them by any amount, without introducing unwanted artifacts. Shapes
are similar to imported PDF objects in that they’re completely resolution independent.
As with all objects in Motion, you can save a shape or a shape style to the Library. This
means that once you create or animate that shape, or both, you can save it to the Library
for use in a future project. You can also save just the style of a shape—such as a custom
gradient fill or modified brush stroke.
1064 Chapter 17 Using Shapes, Masks, and Paint Strokes