In this section, we are going to discuss masking and editing layers and solids. We are going to mask off or cut out parts of the solids to create a shape. The following steps will illustrate how to do it:
Create a 1,920 x 1,080 comp.
Create a new solid layer layer, | New solid, or Ctrl + Y or command + Y for macOS.
Make the solid yellow.
Look at the top-right of your tool bar. Under the Rectangle Tool, you have a variety of masking shapes to edit your solid. These are the masking tools that shape with After Effects. You can choose a Rectangle Tool, a Rounded Rectangle Tool, an Ellipse Tool, a Polygon Tool, or a Star Tool:
We are going to practice using an ellipse tool to cut out our shape:
Choose Ellipse Tool
Choose where you want to create your shape
Click and drag
When dragging these tools, the mask may stretch. If you don't want that, hit Shift while dragging. That will create a perfect shape.
Click once on one of the squares in the bounding box, and insert an image of the masking solid:
The square will fill and you will get bezier handles. This enables you to edit one single mask point:
Double-click one of these squares.
You will get a square bounding box.
Drag this bounding box to edit all the points at the same time:
This is masking off the rest of the solid. Under the properties for masking, there is a mask column where you can choose other parameters. This will hide your mask or give you different masking options.
You can take these basic shapes and make other more complex shapes. You can also change the color of the mask by clicking on the color box in the mask. After Effects also has other parameters that you can work with. Clicking on the mask gives you other parameters that can be edited. You can edit this mask by adjusting the feathering parameter. Adjusting the feathering amount means the outside of the mask will be feathered. Of course, the feathering is able to be key-framed. You can expand the mask as well. The expansion can also go the opposite direction, so you'll actually be eating into the mask in the negative direction. I'd like for you to experiment with all these mask-editing parameters.
Masking is a very powerful tool used for roto scoping and creating shapes. You have control over how your mask will behave, and you can choose to add or subtract from your mask shape. We will focus on the subtract feature:
Drag another shape on top of the current solid shape.
Find the new mask parameter on that solid in the lower-left side of the timeline.
To the right of the mask is a tab called Add with an arrow pointing down. Click on that.
Choose Subtract from that list:
See how it cuts that shape out? This is how you can create interesting shapes in After Effects. Have a lot of fun with this; there's so much you can do with it—the sky's the limit! Masking becomes very important when you need to cut layers, videos, images, and so on. Think of layers as scissors to cut out what you don't want to see. I'd like for you guys to play with these shapes. Start editing these mask points. You can create complex interesting shapes with these techniques.