The Composition and Timeline Panels
All of your compositions can be represented in the Composition and Timeline panels, which open automatically whenever you create or open a composition. These two panels furnish you with different ways of looking at a composition and manipulating its layers. This section gives you an overview of each panel, emphasizing how panels show layers along with their spatial and temporal relationships.
The Composition panel
The Composition—or Comp—panel (Figure 4.24) displays the layers of footage visible at the current frame of a composition. You can use the Comp panel to visually preview the way a composition's layers are rendered within the visible frame as well as how those layers are placed outside the frame (in the pasteboard area). The Composition panel is where you'll find the controls for viewing composition layers (many of which are shared by the Footage and Layer panels) as well as those for setting a composition's current frame and resolution. You can move and scale layers and masks directly in the Comp panel, and you can also view information such as layer paths, keyframes, and tangents. The Comp panel also includes a few buttons that will be discussed in later chapters. A discussion of the Region of Interest (which is also available in the Footage and Layer panels) and Fast Preview buttons is reserved for Chapter 8. Chapter 15, "3D Layers," covers the Camera View pull-down menu along with other features pertaining to 3D compositing.
Figure 4.24 The Composition panel.
The Timeline panel
The Timeline panel (Figure 4.25) graphically represents a composition as layers in a timeline. A vertical line—called the time marker—corresponds to the current frame pictured in the Composition panel. In the Timeline panel, each layer occupies a row, and the rows are stacked vertically. (Unlike the tracks of many nonlinear editing programs, each row contains only one layer.) Layers that are higher in the Timeline panel's stacking order appear in front of lower layers when viewed in the Composition panel. The Timeline panel offers more than just an alternative view of the composition; it gives you precise control over virtually every attribute of each layer in a composition.
Figure 4.25 The Timeline panel.