Nodes · Masks

Cryptomatte

Masksv1core

Overview

Pulls clean anti-aliased object mattes from a cryptomatte render pass: type object names (comma-separated) and the summed coverage becomes the matte — true partial coverage at AA/motion-blur edges, unlike hard ID mattes. preview shows the classic random-colour segmentation.

How to

--- node: Cryptomatte ---

How-to

Wire the render that carries the cryptomatte pass — a Read of the EXR (Houdini, Arnold, Blender, Nuke's own) or an EngineRender — into the node.
Layer Selection picks the family to decode (CryptoObject, CryptoMesh, CryptoMaterial, …); left on auto it takes the first the stream carries.
Arm the Picker and Ctrl+click objects in the viewer: each click adds the object under the cursor to the matte list, or removes it if it is already there. The manifest browser lists every named object; click a name to toggle it. Clear empties the list. Without a manifest the picks are kept as raw <hex> ids and still decode.
output alpha passes the picture through with the matte in its alpha (Nuke's default); matte gives the matte alone; preview paints every object in its own colour with the picked ones lit yellow. preview toggles that colouring in any mode.
unpremultiply divides the picture by the matte; remove_channels drops the crypto layers from what the node passes on; manifest_file names a sidecar manifest when the header has none.

Inputs

Input	What it takes
in	the image this node works on

Outputs

Output	Type
out	Image

Parameters

Parameter	Type	Default	What it does
slot	Int	910	The live-stream slot this node reads. Slots are process-wide; the same number in two nodes is the same stream.
format_width	Int	1920	Width in pixels.
format_height	Int	1080	Height in pixels.
layer	Text		Which channels or layer the node reads or writes.
matte_names	Text		The objects to pull, comma-separated, as named in the manifest. Click objects in the viewer to add them.
output	Choice	matte	matte: the summed coverage of the named objects; preview: the classic random-colour segmentation to pick from. `mattealphapreview`
preview	Bool	false	Show the coverage preview — every object in a random colour — instead of the matte, to find the names.
unpremultiply	Bool	false	Divide the picked matte out of the colour so the object's edges are unpremultiplied for a key or a grade.
remove_channels	Bool	false	Drop the cryptomatte's own layers from the output, leaving the picked matte and the image.
manifest_file	Text		A sidecar manifest (JSON) naming the objects, when the EXR does not carry one.
disabled	Bool	false	Bypass: the node passes its first input through untouched (D in the graph). The knobs keep their values for when it comes back.
label	Text		A note shown under the node in the graph — what this node is FOR. Never affects the render or the cache.
hide_input	Bool	false	Draw the node without its input wire — a tidy graph for a node whose source is obvious (a Dot, a viewer tap).