What I want to achieve is the ability to render light grouping and crypto ID layers together.
Firstly, I tried using the "render setting" node to render crypto layers and light grouping Aovs, but Nuke couldn't recognize this ID layer. According to the documentation, "render product type" must be Arnold in order to render crypto. However, after changing the render type to Arnold, all AOVs disappeared.
In addition, I also tried to use the "Arnold render setting" node, which also requires checking "Arnold product type". Only after rendering the ID layer can Nuke recognize it. If not checked, Nuke still doesn't recognize it. Here, I can get a usable ID layer for "crypto", but the problem with "arnold render setting" is that it cannot use light grouping, I tried many methods and spent several days, but to no avail..
My Houdini version is 20.0.547, and my friend uses the first method, which seems to work. His version is 19.5.