Thanks for the link !
It seems related indeed, however from what I understand of the description, it only handles AOVs defined by custom shading outputs in materials. I will try it to confirm that.
In the case of LPEs, an AOV would be defined by a regular expression identifying a subset of light paths, like CD+L identifying all diffuse-only paths. More information here:
- https://github.com/imageworks/OpenShadingLanguage/wiki/OSL-Light-Path-Expressions
- Light Path Expression AOVs - Arnoldpedia - Arnold Renderer
- Light Path Expressions
I’m quite new to Cycles development but I no dev is planned or have been done for LPEs I might go for the dev myself, depending if our artists really need the feature for the production.
I already implemented it in our in-house renderer using LPE parsing utilities from OSL, but it was a CPU renderer only, I wonder how hard (and efficient) it would be to have LPEs in a GPU backend 