Apple Motion 4 - Manual (Page 1082)

When using an airbrush or image brush preset, the Paint Stroke tool creates a shape
outline that is comprised of dabs. Dabs—analogous to the cells of a replicator or particle
emitter—define the appearance of the stroke. While particle cells emit a variety of different
particle types, airbrush paint strokes have only a single dab type. The dabs can be very
close together or spaced widely apart along the stroke. The dabs’ color, opacity, spacing,
scale, angle, and so on can be modified in the Inspector once a stroke is created.
For more information on modifying a paint stroke after the stroke is created, see Stroke
Pane Controls in the Inspector .
Paint strokes can be animated using behaviors or by keyframing. In addition to Basic
Motion, Simulation, and Parameter behaviors, shapes have their own category of behaviors
that includes a behavior that allows you to sequence effects over the length of the stroke.
For more information on using the Shape behaviors, see
Shape Behaviors .
Note: The stroke’s shape (defined by its control points) and open/closed state can be
modified in the Canvas or Inspector. Because a stroke is a shape, it can be edited just like
any other shape, using the methods described in
How to Edit Shapes .
Once you click the Paint Stroke tool in the Toolbar and prior to drawing the stroke in the
Canvas, you can define the color and other attributes of the stroke in the Paint Stroke
Tool HUD. In the HUD, you select a preset shape style to use as your brush source.
There are several ways to set the style of a paint stroke:
• Select a preset shape style in the Paint Stroke Tool HUD prior to drawing a stroke. If no
preset shape is selected prior to drawing a stroke, a basic solid stroke (outline) is created.
• Modify a paint stroke created with the Paint Stroke tool using the Shape Style pop-up
menu in the Style pane of the Shape Inspector.
• Select the Outline checkbox and modify the outline of a shape (circle, rectangle, and
so on). The Outline checkbox can be selected or deselected in the Shape HUD or the
Style pane of the Shape Inspector.
• Drag a shape style (in the Shape Styles category) from the Library to the paint stroke
object in the Layers tab. The style of the shape from the Library is applied to the paint
stroke.
Depending on the effect you want, you may achieve better results using a stylus and
tablet with the Paint Stroke tool. Many styles and brushes take advantage of the pen
pressure and speed applied when creating the stroke using a graphics tablet. You can
apply the pressure or speed to different stroke parameters, such as width, opacity, and
spacing. For example, choosing Width from the Pen Pressure pop-up menu in the Paint
Stroke Tool HUD results in wider strokes when you apply more pen pressure.
Note: Speed can also be read when using a mouse rather than a stylus.
1082 Chapter 17 Using Shapes, Masks, and Paint Strokes