How do I make a clipping mask layer in After Effects?

To create a clipping mask in After Effects, you use the Track Matte feature, referencing a shape layer.

Steps to create a clipping mask

1. Prepare your layers: You'll need two layers. The first is the layer that will be clipped, and the second is the shape layer that will act as the mask.

2. Arrange your layers:

   • Place the layer you want to clip above the shape layer you want to use as the mask in the layer panel.

3. Apply the Track Matte:

   • Select the layer you want to clip.

   • In the Track Matte dropdown menu for the layer you selected, choose the shape layer you want to use as the mask.

   • Select the option "Alpha Matte" or "Alpha Inverted Matte".

     • Alpha Matte: The layer is only visible within the bounds of the shape layer.
     • Alpha Inverted Matte: The layer is visible only outside the bounds of the shape layer.

   • As explained in the provided reference, by selecting the shape layer from the "Take mat from layer" drop down, it applies a clipping mask.

Example

Let's say you have a star image and a circle shape. You want to show the star image only inside the circle:

• Star Layer: This is the layer that will be clipped.
• Circle Layer: This is the shape layer acting as the mask.
• With the Star Layer selected, go to the Track Matte dropdown menu and select the Circle Layer as the matte source.
• Choose Alpha Matte.
• Now, only the portion of the star image within the circle will be visible.

Key Takeaways

• The shape layer must be below the layer you are clipping.
• Use the Track Matte option within the layer settings.
• Select either Alpha Matte or Alpha Inverted Matte to control the visible areas.

By using the Track Matte feature, you can effectively create clipping masks in After Effects, allowing you to reveal portions of layers using the shapes of others.