Apple Motion 3 - Manual (Page 1000)

1000 Chapter 12 Using Shapes and Masks
B-Splines can also be used to draw shapes, but unlike Bezier controls, B-Splines are
manipulated using only points—there are no tangent handles. Furthermore, the points
themselves do not lie on the surface of the shape. Instead, each B-Spline control point
is offset from the shape’s surface, pulling that section of the shape toward itself as if it
was a magnet, in order to create a curve. By combining the influence of multiple B-
Spline points, you can create different curves. B-Splines are extremely smooth—by
default, there are no sharp angles in B-Spline shapes, although you can create sharper
curves, if necessary.
Because B-Spline controls are so simple, they’re easy to animate and manipulate. The
tools you use for a particular task are largely a matter of personal preference.
Note: Shapes drawn with Bezier and B-Spline tools can be converted into paint strokes
by selecting the shape’s Outline checkbox and choosing a different brush type in the
Inspector. For more information, see “
Creating Paint Strokes ” on page 1012.
Drawing Masks and Shapes Using Bezier Splines
This section describes how to draw a Bezier shape from scratch. These methods are
identical whether you use the shape or masking tools. This section focuses on drawing
shapes. For more information on drawing masks, see “
Masking Layers to Create
Transparency ” on page 1087.
To draw a Bezier shape:
1 Click the Bezier tool in the Toolbar (or press B).
Note: The Bezier Mask tool is located in the Mask tools section of the Toolbar.
B-Spline control point
Bezier tool
Bezier Mask tool