Two-sided SDF is generated when you import (or hit apply in the static mesh editor) and either you have enabled “force two-sided SDF” or your default materials in the static mesh are two-sided.
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They changed the name (in a more positive way). This is becoming serious and mainstream!
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wdym? i haven’t touched the source in a couple weeks. out of space. it’s MEGAlights now? ohh well…
maybe change it to SSRTMLS - OIRTINAWUJSTADFS aka screenspace raytraced multilight shadows - or if raytracing is not available we use just screentraces and distance field shadows. 
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Honestly I’m just excited the tech is moving into experimental. It’s always surreal talking about experimental stuff such as this with other devs, and I forget that a lot of the stuff we experiment with isn’t even live yet. I like MegaLights as a name, it’s descriptive and fun at the same time. The main thing I’m excited by is just that we now have a lighting solution that can coherently handle basically anything you can render to screen, and theoretically hundreds of scene lights at once.
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Is it something similar to the RTXDI where you can render hundreds of local lights without experiencing a performance hit?
In our archviz app, users can place lamps manually into the scene and there are many cases where there are many overlapping local lights which cause a big performance hit (think of big, open office rooms with lots of ceiling lights closely packed), would be great if this would provide a solution for such cases. Of course such rooms are easy to fake by combining many lights into a single one, but not all users have an technical understanding of it and it is not always possible with an archviz scene.
Basically, yes.
Longer version: it’s Epic’s version of RTXDI tuned for UE-specific use cases. The wrinkles in MegaLights are that it’s designed to handle local lighting while directional lighting remains its’ own thing, it’s more tuned for hundreds of lights than thousands, and it can use many different tracing methods (screen, DF, HWRT, etc) to scale across platforms.
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What’s the connection between MegaLights and VSM? Can they be used together, directional lights VSM, other lights MegaLights?
Or VSM for Nanite heavy scenes and MegaLights for non-Nanite usecases?
MegaLights gets a lot of love according to the git commits and VSMs were never really that great IMO due to the reliance on Nanite. So are MegaLights the new cool shadowing technique?
That seems to be the idea, VSM for directional/hero lights and MegaLights for supporting. I read a bit on GitHub about how VSM/Megalights can now interact in some way, but I don’t know what I’m looking at so I won’t speculate.
Real time Path Tracing is finally coming to Unreal 5 using Restir!
But maybe only in the Nvidia branch:
Real-Time Path Tracing in Unreal Engine 5
October 1, 2024
4:15 PM-5:15 PMPT
Games
Room 431
This session will provide a demonstration of real-time path tracing in UE5 running on today’s hardware.
The demo makes use of ReSTIR importance sampling technology to achieve, for the first time ever, path-traced lighting in Unreal Engine.
Come join us to learn what you can do with real-time path tracing to achieve visuals that match the offline Path Tracer in UE5.
By Richard Cowgill
RTX Technology Evangelist
NVIDIA
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Lumen GI makes material AO not work properly.
EDIT*
Material ao seems to work fine. the issue was more caused by the screen percentage with TSR… lsing detail and blurring it out…
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