Johnson Martin writes:
Since version 2.8, Blender has supported the cryptomatte standard for generating compositing masks in Cycles. And more recently, since Blender 2.92 Alpha, this feature has been expanded to support Eevee along with support for Shader AOVs. If you come from a VFX background, you might've used cryptomattes or AOVs before. But if you're a long-time Blender user like me, this feature is probably new to you. So in this guide, I'm going to walk through how to use cryptomattes and AOVs to your advantage in Blender. Whether you're an artist doing VFX work, product development, or any other kind of Blender project, these tools could be useful to you!
