What is a Mask Layer in After Effects

When it comes to professional video editing, Masks are one of the most commonly used functions when animating. Have you ever tried to draw a Shape in Adobe, and, even though you clicked the Rectangle tool to create the object, you ended up activating some strange way of selecting areas? We present you Masks in After Effects.

Masks can be created in the same way as a shape. That's why this feature also allows the user to choose between using masks by default or making new ones. But what exactly does a Mask work for in After Effects?  

A mask is a tool that allows you to include or exclude specific parts of a layer in order to add sharpness or define transparency as many times as you want to in your compositions.​​

To use this way of correctly selecting and not end up drawing a shape, first go to your Timeline and hit the layer you want to mask. Make sure you have your layer highlighted, then tap the Rectangle button.

You will know you are using the correct function if a new numbered element appears below your layer (usually called Mask 1) and if a no-colored square forms on your screen.

How to activate preset and custom masks in After Effects

• To activate the preset masks, select a layer from the Timeline and immediately tap Q or click the Rectangle tool. 
• Click and hold onto the Rectangle button to choose the shape of your mask. You can select one of five options available in After Effects.

• Draw the shape of your mask around one of the objects of the selected layer, leaving inside of it only the elements you want to keep visible.

• To create a custom mask, use the Pen tool. This way you'll be able to delineate the edges of a particular element on your layer. You can also hit G to start outlining.

• Remember that the same functions that work for masks also work for drawing elements in After Effects. This means if you need to design a custom object on your canvas, the same Pen tool you used for mask shapes can also help you with that.