You can use the Cutter node to cut out parts of a layer. You can also use it to only show certain parts of a layer by enabling its Inverted parameter.
- Select a drawing layer.
- Click the Add Layers button and select Effects > Cutter.
The Cutter effect is created as a child of the selected layer.
- In the Timeline view, create a new layer, which will be used as your Cutter effect's Matte layer.
- In your new Matte layer, draw the shape that you want to cut out from your drawing layer.
- In the Timeline view, click the Collapse/Expand button on the effect layer to display its Matte parameter.
- Drag and drop your matte layer next to your Cutter layer's Matte field, under the Parameters column.
- If you want to invert the Cutter's effect, double-click on your Cutter layer to open its Layer Properties dialog, then enable the Inverted option.