Cryptomatte
Cryptomatte is based on the work of Jonh Friedman and Andy Jones at Psyop See their demo video on Vimeo
Cryptomatte is based on the OpenEXR file format. 3D renderers that support it can embed metadata and special render-passes that allows the Compositing application to extract precise masks corresponding to assets/objects/materials.
In Autograph, Cryptomatte is handled in the properties of the Reader of the EXR file
When Enable Cryptomatte is disabled, the Reader will output pixels based on the Output Part parameter selector. Wen enabled, the Output Part selector is disabled and the Cryptomatte controls determines what is output.
The Layer Source controls which Cryptomatte layer is considered as objects list source. In some files, there may be multiple EXR layers containing different Cryptomatte objects informations. For example, Blender exports Assets/Objects/Materials layers.
The Matte list contains a list of names corresponding to objects/assets/materials that were encoded as masks in your EXR file. The + menu lists all available objects and can preview masks while hovering the menu with your mouse.
If the Crytomatte layer contains 256 objects or more, they will not be displayed in the + menu
Mattes can be added either from the + menu, or by clicking on the picker icon and picking the objects right within the viewport. The dropdown on the right controls whether the picker adds or removes picked masks from the list.
The Expand Wildcards parameter allows to specify matte names with '*' and '?' wildcard expressions The '*' character is used to match zero or more of any charaters. The '?' character matches any single character. The '\' character can be used to escape the wildcard characters if the names of the object contain those characters
If the Cryptomatte list contains Screen01, Screen02, Screen03, typing Screen* would match all 3 objects.
The Matte List is by default shared amongst every instance of the EXR Reader. To have the EXR on multiple Autograph layers have a different Matte List, first unshare the Matte List parameter so that it becomes local to the layer.
The Output Mode parameter controls what is visible in output
Matte Over Colored Preview
Outputs the selected mattes in white and the rest of the unselected objects with a random color
Colored Preview
Outputs the unselected objects with a random color
Selected Matte
Outputs the selected objects masks in the RGBA channels