Masks

Overview

The V-Ray Masks are used to refine only selected parts of the rendered image in the VFB. They can be applied to Color correction layers and also to Folders in the VFB layers tree.

When one or more masks are applied to a Folder or Color correction layer, a mask icon is placed in front of it in the layer tree to signify that a mask is present. The parameters of each mask are available in their own separate tabs to the Properties of the masked layer or folder.

The masked areas are defined by selection of objects, materials, groups, layers, etc. To specify them, the respective render elements must be available in the rendered image. Currently, there are three Mask types: Integer Mask, MultiMatte Mask, and Cryptomatte Mask.

UI Path:

||V-Ray Frame Buffer|| > Layers > Add button
||V-Ray Frame Buffer|| > Layers > New Layer right-click menu option
||V-Ray Frame Buffer|| > Layers > Color Correction properties > Add new mask layer button

Parameters

The following parameters are common for all masks:

Blending – Determines how multiple masks are blended together over a single correction layer:

Overwrite – Sets the current mask as it is, without blending it with the masks before it (standing on its left).
Add – Adds the current mask to the result of all masks before it. This is the default mode.
Subtract – Subtracts the mask from the result of all masks before it.
Multiply – Multiplies the mask with the result of all masks before it.
Divide – Divides the mask by the result of all masks before it.

Element – Specifies the render element from which the mask is read. Only render elements available in the rendered image, and compatible with the mask type are listed in the drop down.

Show preview when selected - When enabled, shows a preview of the mask, if the mask is selected.

Invert mask – When enabled, inverts the mask results.

– Allows you to add a new mask layer.

– Shows all tabs of the currently selected color correction layer.

MultiMatte Mask

The MultiMatte Mask is based on the Multi Matte Render Element.

Use red – When enabled, uses the red channel as a grayscale mask.

Use green – When enabled, uses the green channel as a grayscale mask.

Use blue – When enabled, uses the blue channel as a grayscale mask.

Use intensity – When enabled, uses the pixel intensity as a grayscale mask.

Integer Mask

The Integer Mask is used with Render ID and Object ID Render Elements. You can choose which IDs should be in the mask.

+/- Pick – Allows you to add/remove items by picking them from the Render View. When activated and the mouse is inside the Render View, a red square indicates where the value is picked from.

Value – Shows the mask ID when the mouse is hovering over the rendered frame. If you click on a selection in the Render View, the current ID is added/removed from the list below, depending on the Pick mode.

New item – A field to type a mask ID manually and then add it to the current selection with the + button.

+ – Adds IDs to the list.

- – Removes IDs from the list.

Cryptomatte Mask

The Cryptomatte Mask is based on the V-Ray Cryptomatte Render Element.

+/- Pick – Allows you to add/remove items by picking them from the Render View. When activated and the mouse is inside the Render View, a red square indicates where the value is exactly picked.

Value – Sows the mask ID on hover over the rendered frame. If you click on a selection in the Render View, the current ID is added to the list below.

New item – A field to type in a mask ID and add it to the current selection with the + button. The text is case insensitive.

+ – Adds IDs to the list.

- – Removes IDs from the list.

Image Alpha Mask

The Image Alpha Mask is based on the rendered Alpha channel.

Show preview when selected – Shows the preview of the image alpha.

Invert mask – Inverts the mask.

Notes

• Currently, there are masks based only on some V-Ray render elements. The different mask types filter the list of all elements and show only the suitable ones.
• Currently, masks cannot be placed directly on a render element layer. A color correction layer must be placed first on the render element, and then the mask is added on top. For example, a Hue/Saturation layer is applied on the RGB color or a Light Select Render Element layer and then a mask is added on the correction layer so that only the masked area has the correction applied.