I’ve been using GPU lightmass in a handful of my own projects. In all of them, one specific flaw with it keeps crawling up and I haven’t seen any discussion about it.
The problem is that GPU lightmass seems to ignore the landscape visibility mask as a transparent surface and casts shadows and illumination as though it were a normal surface.
It doesn’t matter what settings I change on the light on the landscape, I haven’t found anything that would lessen let alone fix the issue.
There are locations in several of my projects that use the landscape visibility mask for caves, staircases, etc but all get their shading cut with this awkward bug.
If there’s anything I can do, what is it?