Lumen | Inside Unreal

On our second week of in-depth UE5 presentations we’re taking a look at Lumen, UE5’s Global Illumination and Reflections system. We’ll walk you through what it is, how to enable it, and what it provides. Plus, a high level overview of how it works and a look at content from the community!

ANNOUNCEMENT POST

**TIMESTAMPS**
00:00 Countdown
05:01 News
07:01 Karma Earners
07:15 Community Spotlights
08:14 Inside Unreal Graphic Intro
08:33 Stream Introductions
09:28 Presentation
10:10 Lumen Goals
13:55 Lumen Features
18:11 Lumen Settings
21:16 Main Controls
21:50 How Lumen Works
23:07 Hybrid Tracing Pipeline
24:32 Mesh Distance Fields
27:39 Surface Cache
32:02 Visualize LumeScene
33:36 Optimization
35:27 Software Tracing Limitations
37:31 Hardware Ray Tracing
47:47 Final Gather
49:41 Ray Traces are Slow
51:56 Screen Space Radiance Caching
52:25 Heavily Downsampled Tracing
53:31 World Space Radiance Caching
53:20 Tracing Summary
55:08 Lumen Final Gather
57:06 Reflections
57:30 Lumen Reflections
58:38 Reflections with HW Tracing
59:29 Lumen Reflections vs Ray Traced Reflections
1:02:14 Best Practices
1:02:29 Emissive
1:04:20 Base Color
1:08:30 Indirect Lighting Intensity
1:09:18 Surface Cache
1:11:03 Platforms
1:14:12 Performance
1:16:53 Hope to have for 5.0 Release
1:17:22 Feedback
1:17:45 History of Lumen
1:19:00 Lumen Content Examples
1:47:30 Quick Break Start
1:53:10 Quick Break End
1:53:14 Question and Answers Session
2:30:05 Information and Stream Wrap Up

[McDROID]

This is so relaxing and refreshing to hear an honest list of limitation and targets. From the devs themselves and not some marketing team...

[mou.]

Came for info about Lumen, forgot why I was even here after watching an egg want to fly.

[glauconariston]

It's quite incredible how Lumen and Nanite interplay and depend on each other. It must have taken a lot of cleverness to make that all coordinate!

[tony]

VR VR VR VR Support, Please! Thank you for your amazing work!

[MaximusPrimusKay]

Honestly, this is a really well done presentation.
Daniel explains the technical features and Chance, just by asking the right the questions, elaborates on it from a more artistic perspective. This really helps to better understand Lumen's use cases and how it improves/differs from traditional lighting methods.

[tk]

Again, another group of experts that care for their product and the community that uses it. Impressive. Inspirational. Sold

[VRDivision]

14:28 Very happy to see a shout-out to Rafael Reis (ue4architecture) he's an absolute legend in the UE Archviz community!

[Silpheedx]

Thank you so very much for bringing out the tech artists and showing such a solid how to. I appreciate this content more than I can say.

[AngelStarStudios]

We're very excited to delve into Unreal!

[Thomason]

the new ideas behind lumen are amazing.
but even more so, how well it is integrated with nanite and superresolution. such a nice combination! mustve been a great collab between the teams!

[daveynorton]

Love the effort in captioning this whole 2 hour video

[KarelChytilArt]

I am watching it always before sleeping ... and have to watch it again and again. Btw great video

[OmarChida]

Daniel Wright is very chilling, funny and humble. I really like this presentation and the way he explains things to even non-technical people. I also appreciate the questions asked by the hosts. Overall this is top notch presentation!

[DillonThomasDigital]

Lumen is a massive, massive, massive, MASSIVE, **MASSIVE** step forward for realtime content creation. This is fucking nuts.

[gabrielceolato]

Rafael Reis is a brazillian monster, i love all his work

[Eternal_]

Thank you guys for making this genius tech possible for us to be more creative

[BradfordSmithD]

"The single biggest impact you can have is clear and bright color textures" is an oversimplification and potentially mis-leading. Yes, more light will be bounced, but photographically speaking, sometimes the environment is what it is (from a design standpoint). Having shot weddings, many times you are photographing a white dress in a dark painted room. It is what it is. You can add reflectors, but you generally don't have that option working quickly. You expose for the relevant subject (brightest), then work shadow visibility in the development (tone-map) and grade (PPV).

Now-a-days, the local exposure (eye adaption is a big leap forward in this respect), but while it will improve visibility into shadow, of course it doesn't necessarily change the color quality of the indirect bounce (which is a separate goal in and of itself). But we can't simply state that making all your textures bright and saturated is correct. It's part of a nuanced, art directed system, and a subjective edit.

[Cheyne]

Why is this video only available in 360p resolution? Please make a higher resolution available as 360p kind of defeats the whole purpose here.

[behrampatel]

The lumen screen trace debug screen at 23:42 is one of the most trippy shaders I have seen.I hope we can render scenes with that pass.

[RC-]

1:57:51 he's answering the question of using Lumen as a preview, but from what I can tell the question was about using Lumen for final quality light maps. I.e.: baking faster than lightmass. Even though the mentioned preview issues would likely still apply.