Lumen no longer working in UE5.5 DX11 SM5

Yeah it’s only in main not 5.5.4

As a solo junior technical artist, lumen was really helpful in offloading a lot of work on my end. i am dying to get it back. vulkan is sadly not an option for us since we plan to run it on consoles as well as pc.

i cant understand why epic would switch it off.

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For anyone using Unreal 5.5 built from source that needs Lumen back, you can cherry-pick this commit to your engine’s repo. And enable the CVar (do the same in the video above). It should do the trick, fixed for me when running my game on old machines, the lumen just breaks when I upgrade the engine from 5.4 to 5.5.

Commit: https://github.com/EpicGames/UnrealEngine/commit/b06de9ae3eda937c32a7a3fbec13c3b3165b43ff#diff-0e525a38abd836ee07703d401a18b0f95c120cfb1b9a65b958bffb07e9fb1259
Hash: b06de9a

https://github.com/uno1982/UnrealEngine/tree/5.7-Lumen-D3D-SM5-Fix

Update for 5.7 since shader crash using the cvar that brought it back in 5.6
r.Lumen.Supported.SM5=1

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I’ve bumped the branch to 5.7.1 and included some fixes.

Not surprised to be honest, DX11 is bordering on legacy graphics API with limitations on new tech, Lumen and such features like raytracing have no room to scale. I don’t see why you would need to use DX11 but I can why big studios would not want to leva it behind with all the work they put into their engine making DX11 scale better with modern CPU’s