In BlendLuxCore, this is possible for the following light types:
- sky
- sun
- infinite (aka "HDRI" in world or hemi settings)
- constantinfinite (aka "flat color" in world or hemi settings)
The setting can be found in the "Visibility" panel of the lamp properties.
https://wiki.luxcorerender.org/BlendLux ... Visibility
In LuxCore, it is also possible to set these flags on materials, however this was apparently never exposed in BlendLuxCore (I guess I simply forgot it).
However, I have a comment in the area light code:
https://github.com/LuxCoreRender/BlendL ... ht.py#L322# Note: do not add support for visibility.indirect.* settings, they are useless here
# because the only sensible setting is to have them enabled, otherwise we lose MIS
The problem was that making an emissive material invisible to certain rays creates excessive noise because of missing MIS.
I'm not sure if this new hybrid back/forward feature would be an exception to this rule?