- User Data (named userid) is applied to each object that is required a user AOV. You can define any custom name for the objects in the userid parameter, they are used as the IDs in the custom user AOV.
- Add an attribute to the robot's shape geometry node (Attributes > Add Attribute). Type 'mtoa_constant_userid' in the field next to 'Long name'. Note that you must use lower case letters. Capital letters will not work. Change the Data Type to String.
Object2 custom name used in userid User Data for objects
- Create a Custom AOV called crypto_userid.
crypto_userid custom AOV
- Create a cryptomatte shader and under AOV name, enter crypto_userid.
- Set userid as the Source User Data in the shader.
Cryptomatte shader with crypto_userid AOV name and userid as Source User Data
Connect the Cryptomatte shader to the Custom AOV -> Shader of the AOV.
- Render the scene. You should be able to view the crypto_userid AOV.