To subtract a mask in After Effects, follow these steps:
- Create Your Base Shape: Start by adding the shape layer or solid that you want to mask. This will be the primary layer where you’ll be applying the mask.
- Add a New Mask Shape: Drag another shape layer on top of the existing layer with the first mask. This will create a second mask that you will use for subtraction.
- Locate the Mask Property: On the timeline panel, find the newly added mask's parameters within the solid's properties. It’s usually visible in the lower-left side of the timeline under the layer name.
- Change the Mask Mode: Next to the mask name there is a tab named add with a dropdown arrow. Click on it.
- Choose Subtract: From the dropdown menu that appears, select the Subtract option.
This will use the new mask to cut out its shape from the original mask, creating the subtractive effect.
| Step | Action |
|---|---|
| Step 1 | Add a base layer (shape or solid) with your first mask. |
| Step 2 | Add another mask on top of the base layer, with the second shape. |
| Step 3 | Go to the timeline and find the new mask's parameters for the second shape's layer. |
| Step 4 | Click the dropdown named Add next to the mask parameter. |
| Step 5 | Select Subtract from the dropdown menu. |
Here's how to visualise the process:
- You have a circle mask and want to cut a square shape out of the middle.
- You create a circle solid with a circular mask applied to it.
- Next, you add a square layer and apply a square mask to it and place it on top of the circle in the composition.
- You select the square's mask settings from the timeline and change the Add dropdown to Subtract to cut out the square from the circle.
By using the "Subtract" option, the new mask will carve out its shape from the original mask allowing you to create complex shapes and masking effects.
