Creating masks

You can create one or more masks for each layer in a composition using any of the following methods:

• Draw a path using the shape tools or Pen tool. Drawing a mask path is similar to drawing a shape path. (See Create a shape or mask by dragging with shape tools and Create a Bezier shape or mask using the Pen tool.)

• Specify the dimensions of the mask shape numerically in the Mask Shape dialog box. (See Create a rectangular or elliptical mask numerically.)

• Convert a shape path to a mask path.

• Convert a motion path to a mask path. (See Create a mask or shape from a motion path.)

• Trace color or alpha channel values to create a mask using the Auto-trace command. (See Create a mask from channel values with Auto-trace.)

• Paste a path copied from another layer or from Adobe Illustrator, Photoshop, or Fireworks. (See Copy a path from Illustrator, Photoshop, or Fireworks.)

• Convert a text layer to one or more editable masks on a solid-color layer by using the Create Masks From Text command. (See Create shapes or masks from text characters.)

When you create masks on a layer, the mask names appear in the Timeline panel outline in the order in which you create the masks. To organize and keep track of your masks, rename them.

To rename a mask, select it and press Enter (Windows) or Return (Mac OS), or right-click (Windows) or Control-click (Mac OS) the mask name and choose Rename.

When creating additional masks for one layer in the Layer panel, make sure that the Target menu in the Layer panel is set to None; otherwise, you replace the targeted mask instead of creating a new mask. You can also lock a mask to prevent changes to it.

Menu selections to specify a mask to target in the Layer panel

A.

View menu

B.

Target menu

When creating or editing masks, look in the Info panel for information such as the mask name and the number of vertices in the mask.

To create a mask that you can move independently of the primary layer that it’s masking, create the mask on a separate white solid layer, and use that solid layer as a track matte for the primary layer. Then use parenting to make the solid layer a child of the primary layer, so that the mask moves with the primary layer as if it were applied directly. Because the solid layer is a child layer, it can also be animated independently of its parent. You can use motion tracking to make the solid layer (and therefore the mask) follow moving objects in the primary layer. (See Convert a layer into a track matte and Parent and child layers.)