> ## Documentation Index
> Fetch the complete documentation index at: https://docs.pulze.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Masks

> How LayerWise turns multimatte and luminance passes into layer masks, and how nametags name them.

LayerWise builds masks from your matte passes and puts them on groups you can drop adjustment layers into. Warm up the wood, darken the glass, lift the plants, each in its own group.

LayerWise reads three kinds of mask source:

* **Multimatte** elements (*RGB masks*): each of the red, green and blue channels holds one object selection, so one file makes up to **three** masks. Examples: V-Ray MultiMatteElement, Corona CMasking\_Mask, FStorm MultiMatte.
* **Luma mask** elements: the brightness of the whole image is the mask. Examples: Alpha, ZDepth, ReflectionFilter.
* **Cryptomatte** elements: one ID per object or material, so you pick the masks you want after rendering. See [Cryptomatte](https://docs.pulze.io/layerwise/cryptomatte.md).

You set which elements are which in [Render elements](https://docs.pulze.io/layerwise/render-elements.md).

## Nametags

You name a multimatte's three channels in the file name with **nametags**: a wildcard character (`#` by default) followed by a name, in the part of the file name after a dot.

```
cam01.MultiMatteElement.#Wood#Glass#Stone.png
                        └─R─┘└─G──┘└─B──┘
```

The first tag names the red channel, the second the green, the third the blue. This file makes three masks: `#Wood`, `#Glass` and `#Stone`.

![A multimatte with red leather furniture, green windows and blue brick, split into the masks #Leather, #Glass and #Brick](https://mintcdn.com/sourcelinekft/z3vWbLeBmT4OoYjW/images/layerwise/lw_masks_multimatte.webp?fit=max\&auto=format\&n=z3vWbLeBmT4OoYjW\&q=85\&s=c9cc1f5de24b5054aa765e9ec7637a0f)

One multimatte, three masks: the nametags name the red, green and blue channels

In most renderers you do this by naming the multimatte render element itself, for example naming the V-Ray MultiMatte element `MultiMatteElement.#Wood#Glass#Stone`.

* **Missing tags** get a default name from the file name and the channel, such as `MultiMatteElement_R`. Default names have no wildcard.
* **Fewer channels:** you can turn off the red, green or blue channel in [Settings](https://docs.pulze.io/layerwise/settings.md#masks). The other channels keep their tags (turning off green doesn't move the blue tag to green).
* **Another wildcard:** if `#` clashes with your naming, choose `$`, `&`, `@` or `%` in [Settings](https://docs.pulze.io/layerwise/settings.md#masks).

## Luma masks

A luma mask element makes a single mask named `[LUMA]` followed by the element name, for example `[LUMA]Alpha` or `[LUMA]ZDepth`. White in the pass is visible, black is hidden.

## Where the masks go

For each mask (`#Wood`, `[LUMA]Alpha` and so on), LayerWise:

1. **Puts it on every layer or group with exactly that name**, anywhere in the document. Existing masks on those layers are replaced.
2. **Creates a new group with that name** if none exists, at the top of the group the matte layer is in, with the mask on it.
3. **Saves it as an alpha channel** with the same name in the Channels panel, so you can load it as a selection any time.

A completely empty mask hides everything, so an object that's no longer in the shot doesn't leave a stray selection.

![Masked groups in the Layers panel and matching alpha channels in the Channels panel](https://mintcdn.com/sourcelinekft/z3vWbLeBmT4OoYjW/images/layerwise/lw_masks_targets.webp?fit=max\&auto=format\&n=z3vWbLeBmT4OoYjW\&q=85\&s=abf5ae8d9bf952780325ffcb2a41efe0)

Masked groups hold your adjustments; the same masks are saved as channels

> [!TIP]
>
> Put your selective adjustments **inside** the `#Wood`-style groups. Next time you [update the renders](https://docs.pulze.io/layerwise/workflows/update-renders.md), the group masks are regenerated from the new multimatte, and your adjustments follow the objects even if the camera or the model changed.

You can also name an existing layer or group yourself, for example `#Plants`, and render a multimatte with a `#Plants` tag. LayerWise finds it and masks it.

## When masks are made

| Where | What happens |
| - | - |
| [Create new document](https://docs.pulze.io/layerwise/workflows/create-document.md) with **Extract layer masks** on | Masks are made right after each matte is placed. Groups of the template with matching names get them; missing ones are created. Matte layers are hidden afterwards. |
| [Update renders](https://docs.pulze.io/layerwise/workflows/update-renders.md) | **Update existing layer masks** regenerates the masks of existing targets; **Create new layer masks** adds groups for new tags. Both run after any resize. |
| [Extract layer masks](https://docs.pulze.io/layerwise/tools.md#extract-layer-masks) tool | Makes masks from the selected multimatte layers, any time. |
| [Masks from Cryptomatte](https://docs.pulze.io/layerwise/tools.md#masks-from-cryptomatte) tool | Makes masks from the mattes you pick in a Cryptomatte EXR, any time. |


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