A layer mask attaches to a single layer and controls which parts of that layer stay visible — you paint the mask, and the layer shows through only where the mask allows. You manage it from the Layers panel in the sidebar.

When to use

You want to hide or reveal parts of one layer without erasing pixels — the mask is non-destructive and can be turned off at any time.
You need to blend a layer into the ones beneath it (soft edges, cut-outs, feathered transitions).
You want to reuse the same shape across several layers — paint once, then copy and paste the mask.

Layer masks live on image layers (not frames, not video-only layers). If you instead want to paint a region and have the AI regenerate just that area, that’s a different workflow — see Mask & inpaint.

Add a mask

Select the layer in the Layers panel.
Click Add Mask in the layer’s control row. The layer must be visible with opacity above zero — otherwise the button is disabled.
A mask thumbnail appears beside the layer thumbnail, and you drop straight into mask editing so you can start painting.

Upload a mask

You can replace a layer’s mask with an image instead of painting it. On a layer that already has a mask, click Upload in the mask control row and choose a PNG, JPG or WebP. (To import onto a layer that has no mask yet, add a mask first, then Upload over it.)

The image is read as a grayscale alpha map — white keeps the layer, black hides it (the same format that Download mask produces), so a mask you downloaded can be edited in another tool and re-imported. It is fitted to the layer’s image, and once imported it behaves exactly like a painted mask — you can toggle, edit, copy, download or delete it.

Edit a mask

Click the Edit (pencil) button on a layer that already has a mask — or click the mask thumbnail on an already-selected layer.
Paint the mask with the mask tools (brush, lasso, and more). Painting decides which parts of the layer stay active.
Finish editing to save the mask. Your changes are stored to that layer.

The mask is a painted alpha buffer, not a region-regenerate instruction. To paint an area and re-render it with a model, use Mask & inpaint instead.

Turn a mask on or off

Use the On / Off toggle in the control row. On shows a green outline; Off dims the mask thumbnail and marks it with a red X. Toggling off keeps the mask — it just stops applying it, so you can bring it back later.

Copy a mask onto another layer

On the source layer, click Copy (the button briefly flashes a checkmark to confirm).
Select the layer or layers you want to paste onto. A Paste button appears on every selected layer except the one you copied from.
Click Paste. The mask is stamped onto all selected layers at once, fitted to each layer. Pasting silently replaces any mask already there.

Download a mask

Download mask (the download button in the mask control row) exports the mask by itself as a PNG.
Download layer (the download button in the layer’s header row, next to delete) exports the layer as a PNG with its mask already applied.

Delete a mask

Click the Delete (trash) button in the mask control row to remove the mask from the layer. This clears the mask only — the layer’s image stays.

How it works

A mask is stored per layer and painted at the image’s native pixel resolution, so it stays crisp and lines up with the real image pixels even after you resize the layer.
Turning a mask off keeps it attached — it stops applying until you turn it back On.
Most mask actions are unavailable while you’re actively painting a mask or in brush mode; finish or exit first.

Tips

Keep a layer visible to edit its mask — the Add Mask and Edit buttons are disabled when a layer is hidden or set to zero opacity.
Paste hits every selected layer at once — select the full set before clicking Paste to apply one shape everywhere in a single step.
Off, not delete — if you might want the mask back, toggle it Off rather than deleting it.

Mask & inpaint — paint a region and regenerate just that area.
Editor & Canvas Objects — how layers, scenes, and the sidebar fit together.