Apple Motion 4 - Manual (Page 1067)

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.
B-Spline control point
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 .
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
Using Masks to Create Transparency .
To draw a Bezier shape
1 Click the Bezier tool in the Toolbar (or press B).
Bezier tool
1067 Chapter 17 Using Shapes, Masks, and Paint Strokes