The world space radiance cache is close to being able to provide multi-bounce reflections. It just needs to be ‘marked’ with the reflection ray hits, then updated, then interpolated from. There will be significant leaking though, as the probe may be on the other side of the wall.
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That’s pretty surprising, you should see the sky reflection at least for glass at any distance. Try disabling Screen Traces, does that change anything?
It would be interesting to check how it looks like in Lumen Scene Visualization, as this is what Lumen rays actually hit. Even better if you can repro it with a single object and simplified material, which you could share with us, so that we can investigate and fix.
I think I’ve reported this one quite a long ago. Basically the issue was that whenever meshes had a translucent foliage material, which had any part of its base color completely black (RGB 000), it would not be black but it’d glow bright green instead. I had to work around it by putting clamp nodes in all our foliage materials and offsetting the base color from the bottom to get rid of 100% black areas.
It should not be too difficult to figure out of it’s a same bug. Just check if the base color textures has some pitch black spots in it 
Hi - thanks for the tip - I tried it but that doesnt change anything.
I also have an SM_Sky in my scene, the reflection distance is just too limited.
It sounds like your sky exists only as a mesh, and is not being captured by the skylight. You can check what the skylight is capturing by switching to the Lumen Scene viewmode. You can scale up the sky mesh until it’s larger than the skylight’s ‘Sky Distance Threshold’.
I’m getting these really strange streaks when an object moves in front of a reflective surface with high quality translucent reflections enabled…
The first image is without high quality translucent and it looks good, except that it has that hazy fade towards the foot of the mountains and the screen space fade at the edge of the screen. The second image is with high quality translucent turned on, and I get those nasty streaks in the foreground (see weeds/foliage) and the distant mountains aren’t included (is this because I don’t have the world partition hlod set up properly for farfield reflections?)
That makes perfect sense to me, and good to know. I’m aware that the world probes are prone to substantial leaking, but seeing as this would only be N+1 reflection bounces, most of the main occlusion and reflection would already be resolved, not to mention screen traces. Essentially, the reflection just needs to display something that isn’t black to avoid obvious energy loss; in my experience it’s better to have light-leaking for specular than over-occlusion.
That does appear to be the case, yes. Pink means missing from surface cache coverage, if you’re using hit lighting it’s a slightly different story, but by and large, yes. If you want it included in lumen (up to a range of 1km), then you’ll need HLOD.
For as much as I’d really like new graphical features in the pipe for lumen, I think simplifying the HLOD setup would be extremely appreciated. As it stands, the complexity of configuring and visualizing the system often makes it prohibitively difficult to use for smaller projects. I’m often making smaller scenes and tests, and (however challenging this would be to setup), I would love a simple ‘generate HLOD’ button to quickly capture Far-field detail into a scene.
Do you have “Affect Dynamic Indirect Lighting” and “Affects Distance Field Lighting” enabled in your foliage asset? I’ve double checked and Nanite assets placed through the foliage painter work fine on my end.
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Ahhh thank you, I was having the same issue. Somehow I missed this setting.
I deleted my SkyMesh and tried something with the ‘Sky Distance Threshold’ values - unfortunately no sky reflections from a certain (much too small) distance.
Yes, all effects are on. We still cannot see the “Translucency” light reflection in the painted plants with the “Foliage Tool”. So like in the video. But when plants are manually added to scene everything is fine.
Maybe you are missing “Affect Dynamic Indirect Lighting” flag in foliage asset, as now you get AO, but don’t get any color? Best to check how it looks like in Lumen scene visualization.
Could also try “r.LumenScene.SurfaceCache.MeshCardsMergeInstances 0”?
“r.LumenScene.SurfaceCache.MeshCardsMergeInstances 0” yes we tried that too.
Everything is black in the Lumen scene.
Can you check if those foliage assets are Nanite? Just enable some Nanite visualization and see if they are visible there. Lumen currently supports HISM only with Nanite.
Thank you. We were looking for this.
UE5.1 Preview 2. Strange luminescent flickering on the back side of leaves (Megascan Hornbeam Pack but also on other models). The affected parts are under the sphere of the Attenuation Radius of a rectangular light (not with point light) and with Ray Traced Shadows activated.
There won’t be many opportunities to place a rectangular light near trees, but sometimes it happens that the tree is very close to a building with rectangular lights inside.
Ray Traced Shadows disabled
Light Complexity
Seeing really strange surface cache behavior in RealisticRendering in 5.1. On the floor trim, the surface cache probes are bunching up alongside these vertical lines, for no apparent reason. There is no geometric or texture discontinuity there, and each line appears to have ~21 probe or so. All the trim appears to be exhibiting this behavior.
