Lumen in UE5: Let there be light! | Unreal Engine 

Absolutely we will; some of the very recent research that has stemmed from ReSTIR is showing how to do nearly perceptually unbiased illumination in a lot of cases that have been extremely hard to handle. We don't have all the pieces quite yet, but I think anyone smart and familiar with this part of the literature can imagine quite easily how to complete the picture, so to speak.

The "creeping" (technically usually called "ghosting") is from the feedback. Feedback is used to reduce the amount of calculation done per frame to hit framerate. The more powerful the GPU, the more calculations can be done in a single frame and the less feedback is needed, so as graphics hardware gets better the ghosting will get less intense. Of course, there will probably also be improvements in ways to mask "changed" areas for higher priority calculation or dumping of history. EDIT: also note that since the feedback is done offscreen, ghosting is only visible during major lighting changes. That means it won't be noticeable in most real-world use cases, as very dramatic lighting changes are usually only done in conjunction with other effects like particles or other setpieces. The exception is the reflections because they are view-dependant, but of course, reflections in games have always been a bit janky. :P

@@cerebralm my only point is this approach will not work for every use case. I just played Little Nightmares 2 last week, and there is a lot of gameplay in dark rooms where the character carries and aims a flashlight - the real time shadows are critical to game play, and it wouldn't have worked with any delay at all. Of course, for mostly static scenes, and for things like daytime lighting, Lumen is absolutely brilliant though. 🙂

Also it seemed the shadows are wobbling around even for a stable camera position?

The truth of what you said was proved by the release of The Matrix tech demo

un par un par

Wow, you around here, representing the great KALASHNIKOV? SKRA

Yeah i make VR games at work and all this doesnt benefit me at all sadly

SKRAAAAÄAAAAA

There is one god

@@wbhtrb3008 good for you

​@@wbhtrb3008and his name is brian karis from the unreal engine development team

Epic hired everyone with the highest score in that game to help them out

Edit: Ignore this I was misconceiving. You're mistaken. These are all supported by Lumen, but not Nanite. But that brings me to a common misconception. Nanite is *not* a global system. It is enabled per mesh, meaning that anything that requires translucency or other effects not supported by Nanite, can use the traditional LOD system instead and it will render just fine.

@@Jafoss No, actually there's no realtime GI from landscape and foliage because they don't have surface cache. Also subsurface scattering is not showing once you enable Lumen. GI has nothing to do with nanite which is about geometry.

@@spacepirate9882 Ah I see now. I see a lot of people misconceiving the translucency and foliage limitation of Nanite with Lumen, and I wasn't aware of the lack of surface caching with landscape and foliage or the SSS error, so I thought you were with the crowd. Though from what I recall from one of my own projects SSS was working for me with Lumen enabled, unless it's a bug that happened in the new hotfix.

@@Jafoss I still don't get why you're talking about Nanite (virtual geometry) while I'm talking about Lumen (realtime global illumination). Nanite and Lumen are two different things, they are not related to each other in any way. You can use Lumen without using Nanite at all.

that was not a pun, no one is laughing

@@mogmaximus Lumen + brilliant... I'd say that's a pun since we're talking about lighting here. Pretty lame that I have to explain the pun to you. Also, I laughed... so you're wrong twice.

@@thronosstudios No we all see what you were going for. It just wasn't a good pun. If I asked you to describe the sun in one word and you said brilliant, I'd slap you in the face.

I also noticed this. It looks so nice.

same here.

God no, just no, there´s no reason why that shuld happen, and sometimes that annoying ghost gi form the gizmo stays there even if you deselect the object, JUST NO.

1. About 12 minutes 2. Yes, it is controlling the number of frames contributing to the final lighting of Lumen!

genuinely and literally

To me : - LumenScreenProbeGather : The tracing pass of Lumen. Collecting surface data and building the surface cache - DiffuseIndirectAndAO : The injection pass of computed color bleeding and AO to the base color and AO buffers - LumenReflections : The injection pass of computed lumen reflections to the reflections buffer. For optimization : - Global tracing is less expensive than detail tracing in project settings - Final gather quality in post process settings -> Lumen Global Illumination - Quality in post process settings -> Lumen reflections - Cost is heavily tied to screen resolution. Lowering screen resolution percentage with TAA gen 5 enabled (on by default in UE5)

@@spacepirate9882 OOoooh! That is a great answer! Thank you! Gotta get used to the new terminology :) Thank you again!

I remember how much pain it is to configure GI and Final Gathering for Maya - now I use Blender as my main modeling/rendering software.😁

By the way the Use Case room demo seemed to have enabled "Extend Default Luminance Range in Auto Exposure", also inside Post-Processing Volume we need to enable Lumen as Global Illumination method and crank up Final Gather Quality and Quality in order to obtain similar effect as shown in the video. However I am still having this wobbling effect of shadows.

Also there can be this huge shadow artifact on the side wall depending on your sun direction😢.

17:47 Use hardware acceleration. (Post-Processing Volume) Reflection - (Lumen) Reflection Quality (seems not very effective with software ray tracing, for the interior demo scene at least; Haven't tried effectiveness of distance field, but detail/global toggle not working well for interior scene). Final Gather at 4 is most effective.

计算机图形学终于能把4面墙加1个地板给收拾妥当了。

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Pretty sure translucency is supported by Lumen, you can even see it in action in this video demo, at the 5 minute mark you can see glass windows. You might be confusing the lack of support with Nanite. Which is another misconception. Nanite is enabled *per mesh*, it is not a global LOD system, you can use traditional LODs on assets that require translucency, like foliage and glass.

@@Jafoss I’ll have to double check I may be wrong

Reflection plane is realtime and realtime reflection is always performance heavy, if your plane's normal is upward aka its looking to sky, best thing to do is to bake a reflection in to the surfaces and to the bounds of the probe and use screen space reflection, the baked reflection is to minimize the visual visiblity of SSR screen edges smoothing

@@ciixo8510 thank you for the answer. The bad thing is that Lumion didn’t work with baked reflections, at least as I tested. So if I will bake the reflection I would have to bake the whole scene and use the lightmaps instead of Lumion. Am I wrong?

@@andreytrukhachev7417 i'm actually an environment artist in unity HDRP so i don't know much about ue5, but with the logic of baked reflection being just a cube map getting projected on objects, i don't think that ue5 would have a problem with using that and lumen at the same time, and if it currently is in this way, it would probably be doable in the full release!

Epic should make a new Unreal Tournament game with UE5, that would be amazing to make maps for.

Just download EA version) Already good enough to start prototyping stuff