> For the complete documentation index, see [llms.txt](https://animoia.gitbook.io/animoia-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://animoia.gitbook.io/animoia-docs/effects-reference/mask.md).

# Mask

Uses a drawn path to limit where a layer is visible. Every effect below is listed in the sidebar, so you can jump straight to one. Return to [Effects reference](/animoia-docs/effects-reference.md) for stack behavior shared by all effects.

## Mask

Uses a drawn path to reveal, hide, or soften selected parts of a layer. Select a layer, choose the **Pen tool** (`G`), and draw in the viewer. Drawing on a selected non-shape layer creates a mask; selecting an existing mask path lets you continue editing it. See [Pen and Mask tool](/animoia-docs/guide/toolbar-and-tools.md#pen-and-mask-tool).

**Properties**

| Name           | Control | Visual or audible result                                                                                          |
| -------------- | ------- | ----------------------------------------------------------------------------------------------------------------- |
| Mask Path      | Path    | Defines the boundary that separates the visible and hidden parts of the layer.                                    |
| Mode           | Menu    | Chooses whether the path reveals its interior, cuts its interior away, or temporarily leaves the layer unchanged. |
| Mask Feather   | Number  | Blurs the mask boundary into a wider, softer transition.                                                          |
| Mask Opacity   | Number  | Blends the mask influence from fully transparent to fully applied.                                                |
| Mask Expansion | Number  | Moves the mask boundary outward to reveal more or inward to reveal less.                                          |
| Inverted       | Toggle  | Swaps the inside and outside of the mask.                                                                         |

## Stencil

Uses another layer as a matte, so that layer’s channel decides where this one stays visible. Add it from **Effects > Mask** by double-clicking it or dragging it onto a compatible layer.

**Properties**

| Name                | Control | Visual or audible result                                                                                                                                                                                                               |
| ------------------- | ------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Stencil Layer       | Layer   | Chooses the layer used as the matte. Its shape decides where this layer survives, and its own opacity is taken into account, so fading the stencil layer fades the cut.                                                                |
| Stencil Channel     | Menu    | Chooses which part of the stencil layer is read. **Alpha** treats its transparency as the matte, **Luminance** uses its brightness, and the individual **Red**, **Green**, and **Blue** options let one color channel carry the matte. |
| Invert              | Toggle  | Swaps which side is kept, so the layer shows exactly where the stencil used to hide it.                                                                                                                                                |
| Blend With Original | Number  | Fades the matte back toward the untouched layer, so at the high end the stencil stops cutting anything away.                                                                                                                           |


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