Fortnite v40.00 regression: Lumen GI/Reflections unavailable on non-HWRT GPUs; Software Lumen path appears blocked

General Issues and Bug Reporting
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Summary

After the recent Fortnite update that removed the separate Hardware Ray Tracing toggle and unified Lumen/Nanite rendering paths, Lumen GI and Lumen Reflections no longer appear available on some systems. On top of that, quality presets of graphics settings in-game skip from medium to custom, omitting high and epic. SFTW Lumen in UEFN seems to be working on those cards tho.

Please select what you are reporting on:

Unreal Editor for Fortnite

What Type of Bug are you experiencing?

Other

Steps to Reproduce

  1. Use a Windows PC with a non-hardware-ray-tracing GPU, for example AMD Radeon RX 5700 XT.
  2. Install the latest Fortnite version, v40.x or newer.
  3. Launch Fortnite using DirectX 12 rendering mode.
  4. Open Fortnite graphics settings.
  5. Enable Nanite / Virtualized Geometry if available.
  6. Check the Global Illumination and Reflections settings.
  7. Observe that Lumen GI and Lumen Reflections are not available / not selectable.
  8. Observe that the game displays: “Ray Tracing is not supported on this platform.”
  9. Check the Fortnite log file after entering the Athena / Battle Royale frontend.
  10. Observe that Fortnite applies submode/scalability settings similar to:

LogFort: Applied SubMode settings - Nanite 1 | GlobalIllumination 1 | Reflection 1
LogConfig: Applying CVar settings from Section [GlobalIlluminationQuality@1] File [Scalability]
LogConfig: Set CVar [[r.Lumen.DiffuseIndirect.Allow:0]]
LogConfig: Applying CVar settings from Section [ReflectionQuality@1] File [Scalability]
LogConfig: Set CVar [[r.Lumen.Reflections.Allow:0]]

Expected Result

If Hardware RT is unsupported, Fortnite should either:

  1. fall back to Software Lumen / software ray tracing where supported by UE, or
  2. clearly document that Lumen now requires hardware ray tracing-capable GPUs in Fortnite.

Observed Result

  • Nanite is available and works.

  • The graphics settings do not show usable Lumen GI or Lumen Reflections options.

  • The game displays: “Ray Tracing is not supported on this platform.”

  • Logs show Fortnite applying submode/scalability settings that force GI/Reflection quality level 1.

  • Scalability then disables Lumen via:
    [GlobalIlluminationQuality@1]
    r.Lumen.DiffuseIndirect.Allow=0

    [ReflectionQuality@1]
    r.Lumen.Reflections.Allow=0

Platform(s)

Hardware:
GPU: AMD Radeon RX 5700 XT (26.3.1)
CPU: Ryzen 7 5800X
OS: Windows 11 Pro (Insiders)
Rendering mode: DirectX 12
Nanite / Virtualized Geometry: available and running

Additional Notes

Why this looks like a regression:
Previously, Fortnite/UE5 supported Lumen using both software and hardware ray tracing paths. After the newer unified path/update, non-HWRT GPUs appear to be blocked from Lumen entirely, even though Nanite still works.

Please confirm whether Software Lumen / SWRT fallback has intentionally been removed/disabled in Fortnite, or whether this is a compatibility bug/regression in the new Lumen/HWRT gating logic.

Relevant log excerpts:
LogFort: Applied SubMode settings - Nanite 1 | GlobalIllumination 1 | Reflection 1
LogConfig: Applying CVar settings from Section [GlobalIlluminationQuality@1] File [Scalability]
LogConfig: Set CVar [[r.Lumen.DiffuseIndirect.Allow:0]]
LogConfig: Applying CVar settings from Section [ReflectionQuality@1] File [Scalability]
LogConfig: Set CVar [[r.Lumen.Reflections.Allow:0]]

The issue may be caused by Fortnite’s platform/GPU support check selecting a lower GI/Reflection scalability profile for non-HWRT GPUs, instead of falling back to Software Lumen.

Nanite works on the same system, so the issue seems specific to Lumen GI/Reflection gating rather than DirectX 12 or Nanite availability.

r/FortNiteBR: “Lumen no longer working at all after being merged with hardware raytracing?”
User says they previously could enable Lumen + hardware RT, but after the update they can no longer enable it on an Intel Arc B580, despite being on the latest driver.
Source: https://www.reddit.com/r/FortNiteBR/comments/1s1obqf/lumen_no_longer_working_at_all_after_being_merged/

r/FortNiteBR: “Ray Tracing Not Supported On Intel Arc B70 32GB VRAM”
Very useful because it’s a newer Arc Pro card with RT hardware. The post says Fortnite shows “Ray Tracing Not Supported On This Platform”.
Source: https://www.reddit.com/r/FortNiteBR/comments/1swhrho/ray_tracing_not_supported_on_intel_arc_b70_32gb/

Intel Community: “RayTracing not supported in Fortnite”
A user with Arc B580 reports that after the new Fortnite chapter, ray tracing is no longer supported, even though the card should support it and DX12 is enabled.
Source: https://community.intel.com/t5/Intel-Arc-Discrete-Graphics/RayTracing-not-supported-in-Fortnite/m-p/1745360

Epic Developer Community: “Lumen GI no longer compatible on Intel GPUs”
The user says Lumen works fine in UEFN editor, but can no longer be selected in Fortnite video settings after an update that “unified the ray tracing and nanite rendering paths.”
Source: Lumen GI no longer compaitable on Intel GPUS

Lumen GI no longer compaitable on Intel GPUS
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The issue may also affect the preset selection logic. In-game graphics presets appear to skip from Medium to Custom, with High/Epic not being available normally on this system. This seems consistent with Fortnite forcing GI/Reflection quality level 1 after the platform/GPU support check, even though Nanite is available and running.

This is why the issue looks less like a normal settings problem and more like the Lumen/HWRT gating logic is selecting a reduced scalability path instead of falling back to Software Lumen.

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On top of that, it seems incosistent with how the game settings are displayed in the UI.

Settings that are not available for certain GPUs, such as DLSS - Don’t show neither in enum, selected option in the right description panel nor in the description itself.

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FORT-1097660 has been created and its status is ‘Unconfirmed’. This is now in a queue to be reproduced and confirmed.

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Additional information source:

https://community.intel.com/t5/Intel-Arc-Discrete-Graphics/Nanite-Lumen-quot-Not-Compatible-quot-on-Arc-B580-SL-Fortnite/m-p/1746011

https://linustechtips.com/topic/1634419-fortnite-ray-tracing-not-workingcurrently-unfixable/

edit: removed duplicated source

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This is also an issue I am still experiencing. I made a previous bug report about it but this one is a lot more in depth than mine.

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I’ll also include full game log, with hopes it makes it easier to debug this issue.

FortniteGame.log (3.3 MB)

Here are some most likely relavant lines:

Ln 734: LogInit: Build: ++Fortnite+Release-40.30-CL-53093531
Ln 738: LogInit: Engine Version: 5.8.0-53093531+++Fortnite+Release-40.30
Ln 741: LogInit: OS: Windows 11 (25H2) [10.0.26300.8346] (), CPU: AMD Ryzen 7 5800X 8-Core Processor, GPU: AMD Radeon RX 5700 XT,
Ln 711: LogD3D12RHI: Found D3D12 adapter 0: AMD Radeon RX 5700 XT
Ln 714: LogD3D12RHI: Driver Version: AMD Software: Adrenalin Edition 26.3.1
Ln 725: LogD3D12RHI: DirectX Agility SDK runtime found.
Ln 726: LogD3D12RHI: Chosen D3D12 Adapter Id = 0

Ln 1416: LogRHI: Using Default RHI: D3D12
Ln 1417: LogRHI: Using Highest Feature Level of D3D12: SM6
Ln 1419: LogRHI: Checking if RHI D3D12 with Feature Level SM6 is supported by your system.
Ln 1420: LogRHI: RHI D3D12 with Feature Level SM6 is supported and will be used.
Ln 1421: LogInit: Selected Device Profile: [WindowsClient_D3D12RHI]
Ln 2259: LogD3D12RHI: Integrated GPU (iGPU): false
Ln 2260: LogD3D12RHI: Display: Creating D3D12 RHI with Max Feature Level SM6
Ln 2270: LogRHI: Name: AMD Radeon RX 5700 XT
Ln 2271: LogRHI: Driver Version: AMD Software: Adrenalin Edition 26.3.1
Ln 2273: LogRHI: Performing driver check for denylisted drivers.

Ln 879: LogConfig: Set CVar [[r.Nanite.ProjectEnabled:1]]
Ln 881: LogConfig: Set CVar [[r.Lumen.Supported:1]]
Ln 1024: LogConfig: Set CVar [[r.DynamicGlobalIlluminationMethod:1]]
Ln 1025: LogConfig: Set CVar [[r.ReflectionMethod:1]]
Ln 1218: LogConfig: Applying CVar settings from Section [GlobalIlluminationQuality@3] File [Scalability]
Ln 1222: LogConfig: Set CVar [[r.Lumen.DiffuseIndirect.Allow:1]]
Ln 1261: LogConfig: Applying CVar settings from Section [ReflectionQuality@3] File [Scalability]
Ln 1264: LogConfig: Set CVar [[r.Lumen.Reflections.Allow:1]]

Ln 1421: LogInit: Selected Device Profile: [WindowsClient_D3D12RHI]
Ln 1453: LogDeviceProfileManager: Pushing Device Profile CVar: [[r.RayTracing.Enable:1 -> 0]]
Ln 1517: LogDeviceProfileManager: Pushing Device Profile CVar: [[sg.GlobalIlluminationQuality:3 -> 2]]
Ln 1518: LogConfig: Applying CVar settings from Section [GlobalIlluminationQuality@2] File [Scalability]
Ln 1538: LogConfig: Set CVar [[r.Lumen.HardwareRayTracing.HitLighting.Allowed:0]]
Ln 1539: LogConfig: Set CVar [[r.RayTracing.Scene.BuildMode:0]]
Ln 1544: LogDeviceProfileManager: Pushing Device Profile CVar: [[sg.ReflectionQuality:3 -> 2]]
Ln 1545: LogConfig: Applying CVar settings from Section [ReflectionQuality@2] File [Scalability]

Ln 3607: LogCsvProfiler: Metadata set : scalabilitylevel="Medium"
Ln 3608: LogConsoleResponse: User settings scalability group: Medium
Ln 3609: LogCsvProfiler: Metadata set : desktophwinfo="[CPU] AMD Ryzen 7 5800X ... [GPU] AMD Radeon RX 5700 XT [Memory] 32GB [OS] Windows 11 (25H2) ..."
Ln 3610: LogCsvProfiler: Metadata set : usenanite="Disabled"
Ln 3611: LogCsvProfiler: Metadata set : globalilluminationquality="Ambient Occlusion"
Ln 3612: LogCsvProfiler: Metadata set : reflectionquality="Screen Space"
Ln 3968: LogCsvProfiler: Metadata set : scalabilitylevel="MediumOrAbove"
Ln 3969: LogConsoleResponse: User settings scalability group: MediumOrAbove
Ln 3970: LogCsvProfiler: Metadata set : usenanite="Enabled"

Ln 4237: LogConsoleResponse: User settings scalability group: MediumOrAbove
Ln 4242: LogConsoleResponse: Display: Apply Settings:
Ln 4246: LogConfig: Applying CVar settings from Section [GlobalIlluminationQuality@1] File [Scalability]
Ln 4248: LogConfig: Set CVar [[r.Lumen.DiffuseIndirect.Allow:0]]
Ln 4249: LogConfig: Set CVar [[r.Lumen.FinalGatherMethod:0]]
Ln 4263: LogConfig: Set CVar [[r.Lumen.HardwareRayTracing.HitLighting.Allowed:0]]
Ln 4264: LogConfig: Set CVar [[r.RayTracing.Scene.BuildMode:0]]
Ln 4267: LogConfig: Applying CVar settings from Section [ReflectionQuality@1] File [Scalability]
Ln 4270: LogConfig: Set CVar [[r.Lumen.Reflections.Allow:0]]
Ln 4271: LogCsvProfiler: Metadata set : scalabilitylevel="Medium"
Ln 4272: LogConsoleResponse: User settings scalability group: Medium
Ln 4277: LogCsvProfiler: Metadata set : nanitesupportedincurrentmode="Enabled"
Ln 4278: LogCsvProfiler: Metadata set : naniterunning="Enabled"

Ln 4279: LogFort: Applied SubMode settings - Nanite 1 | GlobalIllumination 1 | Reflection 1

Things I’ve tried just in case:

  • Removed custom Engine.ini and GameUserSettings.ini
  • Removed CloudSettings.sav
  • Tested with default config
  • Tested forcing Lumen/scalability through Engine.ini, GameUserSettings.ini, and launcher command line arguments
  • Cleared AMD GPU driver shader cache
  • Cleared DirectX shader cache

The attached log was captured after reproducing the issue again.

It possibly looks something like this, from the log:

User/settings try higher GI
↓
Device profile pushes GI down
↓
Athena/submode applies its own render settings
↓
Final runtime metadata says Ambient Occlusion + Screen Space
↓
Nanite seems fine, Lumen does not

If more people would like to comment on this issue, I’d probably recommend dropping

GPU:
Driver version:
Does the GPU have HWRT ("RT Cores"/Accelerators)? (Y/N): 
DX12 enabled? (Y/N): 
Nanite available/running? (Y/N): 
GI shown as...? (Ambient Occlusion/Lumen): 
Reflections shown as...? (Screen Space/Lumen): 
Message shown is "Ray Tracing is not supported on this platform"? (Y/N):

It might be easier to see troubleshot and check if it’s related to only non-RT cards (It looks like Intel GPUs [as per three mentioned separate reports, including the report of @vslash9] with HWRT are also affected, at least the B580)

edit: formatting, added possible chain what happens, added what might be worth reporting
edit2: include and format more logs

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Also, here’s the video of quality presets casually skipping high and epic and going directly into custom. (And not being able to use the “down” button to go lower when at custom)

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