5

Bezier splines are good for drawing shapes for illustration. The controls used to manipulate
Bezier splines are similar to those found in many other drawing and compositing
applications, so they may be familiar to you. Bezier controls lend themselves to the creation
of precise, detailed shapes. Tangent handles adjust the curvature of the shape on either
side of the control point, and this defines the surface of the shape.
Tangent handles
Bezier control point
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, magnetically pulling that section of the shape toward
itself 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 specific 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.
1115Chapter 20 Using Shapes, Masks, and Paint Strokes