How to; After Effects Masking

Welcome to this how-to STM Blog on After Effects Masking, courtesy of our animation maestro, Jamie! 

We like to share as much knowledge as we have at STM and hope to help anyone trying to learn something, so without further ado, let’s learn a quick tip about After Effects Masking.

First of all; what is After Effects Masking? 

It’s essentially hiding particular parts of an object in your video with, surprisingly, a mask. 

How do I do it?

Glad you asked. It’s really quite simple; in your timeline, select the object you want to mask and then choose either the pen tool or shape tool. From there, just draw over the object in the composition panel. Now the object is kept to your drawn area. If you can’t find the pen or shape tool bar, you can activate it to appear by clicking on ‘Window’ and then ‘Tools’ 

Or, you can right click on the layer and select mask > new mask. This option will create a default highlighted box around your object for you to then reshape as you please by clicking on the points to move them and using the pen tool to add or remove points.

An inside tip

A second tip is that after adding a mask, if you click on the layers drop down, select the new mask sub-heading, you’ll have various options, such as 

  • invert 
  • to reverse the masked area 
  • feather 
  • to add some blur to the edge of your mask 
  • change the opacity of how visible the masked area is 
  • and expansion, to have the workable area outside the mask visible.

You can also create as many masks as you want! 

One thing to remember, after selecting the pen or shape tool, if you see your cursor looking like a box, you’re ready to draw a mask on your selected layer.

However, if it looks like a star, you’re going to draw a shape layer, because you haven’t got a layer selected in your timeline. 

Thanks for reading this blog on After Effects masking! 

Now, be free, go and get your mask on! 

That’s not a post pandemic instruction, just to be clear.


Thank you for taking the time to read our blog on After Effects masking, why not check out these great resources while you’re here?

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