Cryptomatte

 

Table Of Contents

 

Introduction

Cryptomatte is a system developed by Psyop to deliver a robust matte solution for compositing packages. The Cryptomatte solution encodes EXR images with special image data which automatically generates mattes for several of the commonenly needed mattes during post production. This saves time having to generate the matte AOV's manually especially when there are a lot of objects and materials in your scene. Using the Cryptomatte plugin for NUKE or Fusion, mattes can be quickly and easily extracted through picking objects or materials or by entering object names. Cryptomatte in Redshift currently supports several automatic ID Types based on Node Name, Material Name, Redshift Object ID, or Custom User Attributes.

Cryptomatte rendering will automatically force a bucket size of 128 when a render device does not have enough memory.


Beauty Render.

Cryptomatte AOV Example using the object "Node Name" ID type.


The Cryptomatte plug-in can be downloaded at the Psyop Github page. https://github.com/Psyop/Cryptomatte


Creating A Cryptomatte AOV


Cryptomatte ID Types

Cryptomatte AOV Options Menu



Node Name - ID Type

The "Node Name" ID Type uses the object node naming conventions to build individual unique mattes based on object node names.


In this example Cryptomatte is using Node Name based mattes to isolate mattes for each object node in the scene.


Material Name - ID Type

The "Material Name" ID Type uses the the materials in the scene to build unique mattes for each material.


In this example Cryptomatte is using Material Name based mattes to isolate mattes for each material assigned in the scene.


Redshift Object ID - ID Type

The "Redshift Object ID"  ID Type uses the Object ID parameters on the objects you specify in a similar fashion to the Object ID AOV and Puzzle Matte AOV. This Attribute can be found in the Attribute Editor when selecting an object inside of the Redshift properties or by assigning a Redshift Object ID node to objects.


In this example Cryptomatte is using the Redshift Object ID attribute. We assigned them to specific objects allowing us to selectively control the mattes.


Creating Redshift ObjectID's



Multiple objects can share the same Redshift Object ID number if you want to group objects together into a single matte.


User Attribute - ID Type

The "User Attribute" ID Type reads in custom string attributes you have applied to any objects in the scene and uses the attribute names to guide the mattes Cryptomatte generates. This allows you to selectively target and customize the individual mattes naming convention for further control and organization of your Cryptomatte output.


Creating User Attribute Cryptomattes

In the example below User Attributes were applied to specific objects and each object that we wanted to have its own matte was also given an appropriate individual string name to group the objects by. Here we have the tires, floor, wall, license plate, and front windshield & front light in their own matte groups. This allows us to easily customize the objects and names for our mattes using custom attributes.


Specific objects grouped together into their own respective mattes based on the User Attributes we created.



Multiple objects can share the same name if you want to group objects together into a single matte.



Cryptomatte Depth

The "Cryptomatte Depth" value specifies how many objects can exist per-pixel due to overlapping for things like motion blur and depth of field.


Nuke 12 or older does not come with Cryptomatte installed. To use Cryptomatte in older versions of Nuke you will need to install the plug-in.