That’s surprising, could you send me your scene?
I suspect an AMD specific bug, we haven’t tested on AMD yet for this release.
I haven’t seen those phantom red lights before. Do they appear in the same place every time, or randomly appearing? What graphics card do you have?
Could you send me your scene so I can investigate?
5.1 preview 1 is now available. We’ve made a lot of improvements to Lumen GI and Reflections including:
- Two Sided Foliage shading (gather lighting from behind the leaf, scatter it through)
- Better foliage representation with distance fields, fixes over-occlusion on trees
- Better Surface Cache with Software Ray Tracing, shows up in reflections and emissives
- Less noise in GI, especially when the camera is still, and on the High GI scalability level (60fps console)
- Lumen Reflections on Single Layer Water
- Lumen mirror reflections on the frontmost layer of translucent surfaces if you enable ‘High Quality Translucency Reflections’
And a bunch of other smaller stuff.
Please test out Lumen in 5.1 and let us know what bugs you run into in this thread! The timeline for visual fixes is short. We may not be able to fix all of them but we will certainly investigate
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Thank you for your reply 
Happens in a newly created project too, so it is not specific to my stuff. (so you can replicate it like this.)
What I did:
1: Start 5.1PV1
2: New Project → First Person (Blueprint, no RayTracing, Maximum Settings, Desktop)
3: Wait for compiling
4: It is immediately visible, since one of the 4 walls does not receive GI
5: I increased the sunlight to 10 and rotated it a bit, so that the “dark wall” is in shadow but should be lit by GI and placed another wall in front of it to get bouncelight.
6: saw this:
It only happens in one direction - the side of the wall that faces towards Y+ has this issue.
Lumen Scene also is fine, its just not being “rendered” properly in the final composition of everything.
Unrelated to Lumen, but still relevant: 5.1 does not work with amd drivers from earlier this year, unlike 5.0 - after a few seconds it crashes with “d3d device lost” or so. Not sure if this also happens in packaged builds. (If so, that might not be a good foundation for releasing anything with 5.1, unless fixed.)
Nanite also isnt working properly, some meshes are not displayed fully, but still cast their full shadow.
EDIT:
Small meshes going through trees cause a lot of overocclusion:
^^these are practically 1cm wide “cables” (4 of them, one for each corner) holding the whole thing, if I move it aside the overocclusion moves with them.
Something else I noticed: everything got brighter than it is in 5.0 (guess we have more bounce light now?), and trees obviously need to be adjusted to look fine again. (5.1 is not a simple “drop in replacement” for lumen, work will be required to adjust things.)
But I also see improvements with “dark spots”(not on trees, regular geometry) that existed in 5.0, if that is not another bug with AMD. Aside from that, Metal now seems to not be black anymore, especially if instanced.
From first impressions, good step forward - but given my “amd issues” I have a hard time to see what is real, what is a bug.
EDIT2:
The change to SM6 from SM5… that has no impact on system requirements, or does it? (hard to find information on what gpu supports what, with which driver etc.)
Thanks for those detailed replication steps. After setting it up I’m not getting it on an Nvidia card, so it’s looking like an AMD bug. We’ll get it fixed.
Small meshes going through trees cause a lot of overocclusion:
Yes, that’s a limitation of the technique. We’re tracking where in space the foliage is, and treating that as semi-transparent to make up for distance field inaccuracy, but if we do that near an opaque wall then it will cause leaking through the wall. It’s best to workaround by keeping your opaque meshes away from your foliage.
Something else I noticed: everything got brighter than it is in 5.0 (guess we have more bounce light now?), and trees obviously need to be adjusted to look fine again.
One thing I know of is we increased r.Lumen.ScreenProbeGather.MaxRayIntensity to 40 (from 20), which gets closer to reference. The ‘Global’ Software Ray Tracing (Global Distance Field) gives much more accurate lighting on the hit now, a lot of energy was being lost from that before, especially around areas of sunlight in a dark room, or emissives.
The change to SM6 from SM5… that has no impact on system requirements, or does it?
Note that Lumen has not changed requirements, only Nanite and VSM. SM6 does require a much more recent version of Windows. I don’t have the details atm.
My graphics card is RTX3090. Driver version 517.48 WHQL.These red-light pools didn’t appear in the first place. They appear after the scene has been running for a short period of time, and appear in basically the same place every time the scene is opened.
Guess using meshes withoud Distance field for stuff that goes through foliage should work too? Given that its only something minor (in my case) it doesnt need MDF anyway, probably enabled itself by default.)
Thats easy to adjust then, thanks for the exact values.
Thanks for that improvement, I always had issues with lumen “just losing its light” (or energy as you call it) in indirectly lit areas that technically still should have had enough light etc. (made some stupid workarounds for it, its kinda fine now, but having that fixed in the engine is definitely a great thing.)
Oh yeah, forgot about that. But since I am addicted to nanite now, I will probably stick with 5.0 until it is more clear what the switch to SM6 means for your typical user out there. (If you go Nanite once, you never go back. Not needing to care about Static Mesh count just makes my life sooo much easier.)
@Bio_Weapon
You should at least provide him with your driver Version in addition to your already provided GPU information.
And if you can (if this is marketplace content etc.) some reproduction steps. (If needed, build a small scene just with these assets/Settings and upload it to drive and send it to him.)
He wont be able to find the issue like this, especially given the time constraints.
Out of curiosity @ , are there any plans to resolve/improve lumen glossy/ rough reflection quality (unsure if that would be listed under your features readout)? I tested the ExampleProjectsWelcome page on 5.1 and the floor appears extremely bubbly and noisy, even on maxed out settings. Tested on a 2070S.
Failing that, is there any sort of reflections reference mode that could be used to achieve maximal quality?
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Was about to ask the same question. Glossy reflections are still extremely splotchy.
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Also, is there an ETA for rect light reflections on translucent surfaces?
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Seeing really bad surface cache behavior in 5.1, and this isn’t the first instance. It appears whenever I turn on r.RayTracing.Nanite.Mode 1 (for full nanite geo in ray-tracing), and dissapears when I disable it). It looks like areas where the proxy mesh surface cache coverage worked are the spots that are left, and new geo isn’t being shaded.
On that note, are there any plans for the lumen RT ray offset system to be ported to ray-traced shadows? As it stands, RT shadows have major artifacting with nanite without using r.RayTracing.Shadows.EnableTwoSidedGeometry 0, but that has content limitations.
Not sure if this is the right thread, but since the new release the editor feature of Extend Default Luminance Range is not in there anymore.
I was trying to enable it in a project that was originally setup in 5.0.3. But it was not there anymore. In the end I was able to hack it into the engine with the help from this Post
Hi , there has been an improvement in the lighting of the undergrowth but the areas that are too dark with dense foliage persist, especially with plants positioned with the “foliage” tool. Trees placed with single meshes don’t seem to have too dark “cores”.
In the pictures are active:
- distant field lighting for meshes
- ray tracing hardware
- high quality translucency reflections (only for 5.1)
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Looks natural for me. Why you expect to have the trees darker? It’s not a dense tree + sun on floor which is reflected up to the tree. I’m very often in forests and the tree on this screenshot looks natural for me.
Hi Yaeko,
I’ve grabbed latest Release 5.1 code, 6900XT, installed 22.10.1 driver and followed your repro steps. On my end everything works fine and I can’t see any black walls. Any ideas how could I repro it or another project to try? Attaching screenshot how it looks like on my end.
EDIT: actually reproduced it in another level.
EDIT2: You can fix by using “r.Lumen.ScreenProbeGather.Filtering.WaveOps 0”. Also a workaround was submitted to 5.1.
With Hardware Lumen I’m getting this issue with reflections where it looks like the Skylight is visible through objects. Using a mirror reflection for demonstration purposes but this is still quite distracting using materials with higher roughness values:
This is especially noticeable in areas that are supposed to be dark like this
Software lumen looks much better but still appears to have moving vertical streaks
Turning off screen traces, although clearly more noisy, the bright blue light I presume to be from the skylight is gone
Do you have any small, bright red emissive meshes? Check in the Lumen Scene viewmode. Those artifacts look like what happens when the Lumen Radiance Cache captures a really small, bright light source.
If not, could you send me a project that reproduces it?
Glossy reflection quality is something we very much want to improve (and know it’s not good enough), but didn’t get time to work on for this release. We were mostly focusing on 60fps console shippability, and foliage. Hopefully in the future we will have reflections that can scale up in quality.
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r.RayTracing.Nanite.Mode 1 is a new experimental method, it’s not ready for production or expected to be working with other features like Lumen yet.
There was some work on Ray Traced Shadows avoiding self-intersections with Nanite - you have to set r.RayTracing.Shadows.AvoidSelfIntersectionTraceDistance to something non-zero, likely a value between 1 and 5. It’s surprising that it’s not on by default.
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