The Difference Between Shapes, Paint Strokes, and Masks
Shapes are primarily used to create all kinds of visual elements. They work like any other
layer, except that they are created in Motion and are stored in your project file. A single
shape can be used as a background or colored graphic in a composition, or you can create
complex illustrations using many shapes. Each illustration below is composed of shapes
created in Motion.
Character drawn in Motion using Bezier tool
Replicator using Bezier shape
You can create a paint stroke from scratch, or convert an existing shape to a paint stroke.
Unlike shapes that are created one point at a time, a paint stroke is created in one
continuous movement. You can use the stroke as a whole, or create unique graphic
elements that can be drawn on over time. Although paint strokes share the same
parameters as all other shapes, they have additional specialized parameters.
Paint stroke with applied Sequence Paint behavior
Using Shapes, Masks, and Paint Strokes
Masks are used to create regions of transparency in layers. Although shapes work as layers
by themselves, masks must be assigned to a layer to have an effect. For example, if you
have a picture in which you want to isolate the foreground subject, you can create a mask
to cut out the background.
You can animate shapes, masks, and paint strokes using behaviors and keyframes. Shapes
also have their own special category of behaviors. What’s more, you can animate the
control points used to create each shape or mask in your project. This allows you to
animate the actual form of each shape, in addition to the shape’s basic position, rotation,
and scale parameters.