- Create a cryptomatte map in the Slate Material Editor.
- Drag the cryptomatte map onto a Map slot under AOV Shaders in the AOVs tab of the Render Setup window.
- Open the Arbitrary Output Variables window (AOVs tab of the Render Setup window).
- Select the Cryptomatte AOVs that you require and Add them (drag across to the right from the AOV List).
- Render the scene. The Cryptomatte AOVs should now be available in the AOV list in the RenderView window toolbar.
An example scene file can be downloaded here.