Tested out the LoftOffice content pack for a project, and I discovered that it’s breaking lumen GI; in a radiometrically simple scene with nearby puncual lighting, there was an inordinate amount of noise. My only guess is that the high-frequency herringbone ribs on the wall are creating depth discontinuities that are stopping the screenprobegather from sharing samples spacially, but that’s only a guess:
The normals also look quite strange, but that could be the geometry itself.
In terms of real-world workflow, this herringbone geometry is almost a perfect use case for POM if the stepped effect was absolutely required, but it seemed like a problematic issue nonetheless. If you consider this inappropriate content to be @ ing you over, please let me know and I will gladly stop.
This is more a comment than anything else, but I am very excited to test out lumen and the lighting systems in general come 5.4. It seems like there has been a ton of optimization work, ranging from the broader work of thread parallelization and bindless resource support, down to more specific features like GPU instance culling for RT and the new light grid system, and new features like RT translucent shadows, SampledDirectLighting, and more. I don’t know what the actual performance delta might be 5.3-5.4, but I’m very excited to find out.
Few other features I remembered: lumen now supports translucent objects in reflections, true refraction and multiple refraction events, subsurface profile working in lumen hit lighting, better support of volumetric lighting, and better perf overviews.
If there’s anyone migrating from an offline DCC to UE, they’re going to find that lumen is competitive to an offline renderer in almost every use case, assuming use of the MRQ and cinematic settings.
If it’s not possible to play 4 players splitscreen with lumen i don’t care about 5.4’s performance ! lol By the way nobody answered my question, maybe it is already possible in 5.3 ?
Two player is now possible TMK, 4 player seems like a bad/challenging use case for lumen bc you’re already juggling a ton of extra CPU logic, and each scene would need to carry its’ own memory pools for the caches that couldn’t be overlapped.
Thank you very much for your reply !
I’m already using 2 players splitscreen in 5.1 and i’m happy with the performance, to my surprise with a gtx1060 6gb my gpu thread is around 25ms.
Lumen is so cool i can’t imagine to toggle it off. Many thanks to all the people at Epic for sharing your awsome game engine ^^
Additional bug (will report these via bug report as well) when using the instance overlap visualization mode for HWRT lumen, too-fast camera traversal has caused crashes. This has happened multiple times after engine resets, and without any warning.
That said, I’m not sure what the cause is. The crashes triggered consistently in CitySample_Small (default Wp grid enabled, no streaming), and yet I haven’t been able to trigger a crash in the Electric Dreams Demo (default Wp grid, no streaming). This is despite the CitySample having very well-managed and minimal instance overlapping, whereas electric dreams has massive amounts of overlapping geometry. Curious.
Lumen GI and Reflections don’t work on low and medium scalability settings. When I tried to enable Lumen in the editor, I couldn’t understand why it doesn’t work. The reason was that my scalability settings were on low and there is no information anywhere that it doesn’t work on low scalability settings.
It would be nice if the docs told us that we need to set scalability settings to high or epic in order for Lumen to actually work, and also the engine itself let us know that “Lumen is enabled but not really, the scalability setting is low, so it’s not active”.
question for the staff at this point: is there a plan to add atleast an approximate fog/height fog to raytraced reflections?
was just messing around with some stuff. screentraces do the trick, but they leak the foreground in water reflections, for example. i don’t like this at all. also… the cvars for raytracing heigth fog are not working.
btw… i’m impressed how well dlss manages a meager 33 % scale. lil noisy but i get to my target framerate, without roasting the hell out of the lil rig.
i gotta find another cloud display method for sure. and a baseline graphics quality is almost there. hmmhmm
It does exist and it’s enabled via a Cvar (need to find which one). For lumen reflections at least, standalone RT isn’t being maintained OC.
Also, trying to build UE 5.4 RN (the accumulated featureset and improvements is begging to be tested), and builds keep failing because the file size is just absurd. The last build failed after several hours because 310 gigabytes of storage wasn’t enough. If anyone has tips on cutting bloat I would love to hear it.
I haven’t built the editor in a while (specifically because it takes up so much disk space…) but 5.3 took me about ~70 minutes on my 3900x.
One of the pieces of advice I saw on twitter a while back was to ensure you were building from an SSD. I don’t actually know how much difference this makes as I’ve never done an A/B comparison, but in my case I’m using a gen3 NVME drive.
My files are on a quite fast gen4 SSD, I forget the brand but it got very good reviews. There’s not a bad chance I’m just doing something amazingly wrong then, as I know just enough to build the engine and that’s about it. I’m working with a i7 9700k (due for an upgrade in the near future in all likelihood).
on this build topic: not sure what to post. it is a chonky piece of code, yes. but if you’re into testing new features you gotta deal with it.
also… iirc the long compile is only the first time you generate all the precompiled headers. it rebuilds faster. done that back in 5.3. and… well… i haven’t had an luck or code experience to fix the build at this point in time. not gonna pre test 5.4. it is what it is.
That may be true, I just feel like it’s been creeping up in size in pretty significant ways. When I first built a version pre-5.0 it was something like 180GB, getting upto 310+ GB is just a significant growth.
How intelligent is the samplefog btw? It it a 1-1 match for the heightfog?
not really a 1 to1. on the light side it’s good. on the shadow side (backlit) foliage gets a lil dark. i cheesed it with some cover up fog (on the right). also slightly discolored in the center. not sure what i done wrong there.
Since it’s just distance fog it would make sense that it would introduce glowing, although I’m not actually sure if there’s additional attenuation calculations or something more complex they’re doing with the volumetric GI system.
Also, build failed, just wasn’t in a state to be built. Clocked in at 367 GB.
Anyone having issues when rendering sequences with Lumen?
I still must investigate it deeper to elaborate a report, after a work I must ship, but I want to comment earlier (now) that I have seen discrepancies between what you see in real time and what you get when Movie Render queue rendered:
Walls have like a different shadowing (worse when rendered).
Convolution bloom seems to be disabled.
In addition, but not related only to MRQ:
Translucent High Quality reflections only works when Lumen GI is enabled. With baked lighting, glasses will show colored ‘christmass’ glitches.
Ray traced AO doesn’t work fine with translucent surfaces, making them almost black.
I have tried with my custom render preset but also with a basic, almost empty one. And with and without AA override (samples).
