Converting Between Shapes and Masks

Because masks and shapes are created in similar ways but perform different tasks, there are occasions where you may create a shape and later want to convert it into a mask, or vice versa. Changing shapes to masks and masks to shapes is done by changing the object’s position in the Layers tab or by using the Object menu.

Note: Masks are not applicable to 3D paint strokes, 3D particle systems or replicators, 3D text objects or unflattened 3D groups. In order to convert a shape to a mask on such an object, the item must be flattened.

Different options are available when converting shapes to masks, depending on the type of object that is being masked. The following steps apply when converting a shape to a mask on an image-based object (movie or image sequence, images, generator, and so on).

To convert a shape to a mask on an image
  1. Use any of the shape tools to create a shape (or draw a paint stroke).

    Note: You can also add a preset shape from Shapes category in the Library.

  2. In the Layers tab, drag the shape object onto the layer to be masked.

    The shape is converted into a mask. If the layer to which the mask is applied is not centered in the Canvas, the position of the mask will be slightly offset. This is because the position of the converted mask is dependent upon the original position of the shape relative to the center of its parent group.

Note: If the object receiving the mask has previously been scaled, when converted to a mask, the shape will automatically be scaled too, which may produce unexpected results. To convert a shape to a mask on a scaled object, you may want to first set the object to 100% scale or put the clip into a new group and convert the shape to a mask on the group instead.

Note: Converting a shape that has been manipulated in 3D into a mask may produce unexpected results as the shape must be collapsed into a 2D approximation of the 3D shape before it is applied. For more on applying masks to 3D objects, see Masking Objects in a 3D Project.

To convert a shape to a mask on a group
  1. Use any of the shape tools to create a shape (or draw a paint stroke).

  2. In the Layers tab, drag the shape onto the group layer and pause, holding down the mouse button. When the drop menu appears, choose Move Mask To Group.

To convert a shape to a mask on the enclosing group
  1. Use any of the shape tools to create a shape (or draw a paint stroke).

  2. In the Layers tab, select the shape object and do one of the following:

    • Drag the shape onto the group layer and pause, holding down the mouse button. When the drop menu appears, choose Move Mask To Group.

    • Choose Object > Convert Shape to Mask.

To convert a shape to a mask on another shape
  1. Use any of the shape tools to create a shape (or draw a paint stroke).

  2. In the Layers tab, drag the shape object onto another shape object and pause, holding down the mouse button.

    A drop menu appears.

  3. Choose Add Mask To Shape.

    The shape is converted into a mask on the other shape.

    Note: Spline masks are not applicable to 3D paint strokes. The Local 3D checkbox must be deselected in the Stroke pane of the Shape Inspector for the drop menu to appear.

To convert a shape to a mask on a particle emitter or replicator
  1. Use any of the shape tools to create a shape (or draw a paint stroke).

  2. In the Layers tab, drag the shape object onto an emitter or replicator and pause, holding down the mouse button.

    A drop menu appears.

  3. Choose Add Mask To Emitter or Add Mask to Replicator.

    The shape is converted into a mask on the particle emitter or replicator.

    Note: The 3D checkbox must be deselected in the Emitter or Replicator tab of the Inspector for the drop menu to appear.

To convert a shape to a mask on text
  1. In the Layers tab, select the text layer you want to mask.

  2. In the Layout pane of the Text Inspector, ensure the Flatten checkbox is selected.

  3. Use any of the shape tools to create a shape (or draw a paint stroke).

  4. In the Layers tab, drag the shape object onto a text layer.

To convert a mask to a shape
  • In the Layers tab, select a mask and do one of the following:

    • Choose Object > Convert To Shape.

    • Drag the mask between two objects in the Layers tab.

    • Drag the mask onto the group layer and pause, holding down the mouse button. When the drop menu appears, choose Move Shape To Group.