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18 Chapter 1 Getting to Know Motion
About Motion
In Motion, you create 2D or 3D motion graphics and compositing projects with
imported images (such as Adobe Photoshop or Illustrator files), image sequences,
QuickTime movies, audio files, as well as objects created within Motion. These objects
include text, masks, shapes, particles, paint strokes, and so on.
A Motion project is made up of groups that contain layers. All media imported into
Motion, or elements created within a project, are referred to as layers. A layer must live
within a group. The group acts as a “parent” to its layers. You can select multiple layers
within a group to create a nested group. A group can be 2D or 3D.
Cameras and lights can be added to projects. When a camera is added to a project, you
have the option to switch the project to 3D mode or to remain in 2D mode (unless the
project is empty or completely 2D, in which case it is automatically switched to 3D
mode). 2D groups can exist in a 3D project. A 2D group can be nested in a 3D group. A
3D group can be nested in a 2D group. Once a 3D group is nested in a 2D group, the
group is flattened. This means that the nested 3D group acts like a flat card and ignores
the camera. In addition, the flattened group does not intersect with layers of the 2D
group or other groups in the project.
Any transforms, filters, or behaviors that are applied to a group are applied to the layers
within the group. If you move or apply a filter or behavior to a group, all layers within
that group are affected. You can also apply filters and behaviors to the individual layers
within a group.
A filter is a process that changes the appearance of an image. For example, a blur filter
takes an input image and outputs a blurred version of that image. A behavior is a
process that applies a value range to an object’s parameters, creating an animation
based on the affected parameters. For example, the Spin behavior rotates an object
over time at a rate that you specify.
Groups and layers can be moved and animated by using behaviors or by setting
keyframes. Filters can also be animated.
A project represents a single flow of image data built from the bottom up. In a
composite with a single group, the layers within that group are stacked above one
another. Filters and behaviors that are applied to a layer appear beneath the object in
the Layers list. The group represents the image that results from its combined layers
and their applied behaviors, filters, and composite modes (blend modes).