Lumen + HWRT + Landscape = tons of light leakage.
I’m not one to throw Epic under the bus but honestly, WTheck… It just doesn’t-work…
Using SW raytracing
How it should look:
Settings:
Using HW raytracing
Blargh:
Settings:
Using HW raytracing #2
Up close and personal; the sun is behind the ridge and should not be illuminating those parts. Notice that it also impacts the (nanite) grass:
This behavior is present in 5.5.2 and 5.4.4. Lumen doesn’t have to be using HW, just enabling ‘support hardware raytracing’ is enough to make the issue preset.
Enabling/disabling Path Tracing has no effect. I’ve also run the gamut of toggling ray-traced shadows on/off for the landscape itself, the landscape material, in the Project-settings. Two-sided settings on the landscape and/or material make no difference. Using Nanite on the landscape makes no difference either but I will say that at least the shadows on the nanite (vs landscape/heightmesh) are MUCH crisper, for whatever that is worth.
It’s not the material either as I can throw WorldGrid on it and get the same behavior.
I have to honestly ask: is this the expected behavior or am I troubleshooting your product? When I see things like this, and I take the time to figure out what I am not doing wrong, it makes me feel that I am wasting my time w/this engine. Especially when something so basic/fundamental as ‘blocking-light’ doesn’t function across multiple versions.
EDIT: even w/SW raytracing there is still leakage:
5.5.2 SW Raytracing
I’m not trying to sound pissy/insulting w/the above, I know tonality doesn’t come across well in text; I’m just frustrated because the use-case here is so simple.
If you need a testcase, take the heightmap provided in my tutorial as it’s the same one I am using here. Default project, default settings, enable HWRT. Make a landscape, throw a directional light (or UltraDynamicSky) and just-look.
ref - Implementing a landscape with a virtual heightfield mesh. | Community tutorial