---
title: "Crop a layer with a mask"
description: "Reveal part of a layer through a rectangular opening while keeping its drawing intact."
canonical: "https://terminal.lottiefiles.com/docs/how-to/crop-a-layer-with-a-mask/"
last_updated: 2026-10-29
---

# Crop a layer with a mask

Reveal part of a layer through a rectangular opening while keeping its drawing intact.

Start with a shape or image in a local document.

1. Click the layer on the stage. Its selection box appears.
2. Press `:` and type `Draw as mask`. Press `enter` to choose **Draw as mask**.
3. Press `⇧R` to choose **Rectangle** for the mask.
4. Drag a rectangle across the part you want to keep. Only the part inside it remains visible.
5. Press `esc` to put down the rectangle tool.
6. Choose **Draw as mask** in the palette again. Drawing tools now make layers again.
7. Find **Masks** in the rail (the Properties panel in After Effects or Figma). Scroll over
   the rail if needed; the new mask has **add** mode, opacity and expansion controls.

![A circle revealed through a rectangular mask](https://terminal.lottiefiles.com/docs/assets/shots/draw-mask-window.png)

Click **inv** to reveal the outside instead. Click the mask name to edit its points.
For a window controlled by another layer, use a [matte](https://terminal.lottiefiles.com/docs/layers/appearance.md#matte-choices).

Watch: [Masks and mattes](https://terminal.lottiefiles.com/masks-mattes/).