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
- Use a Windows PC with a non-hardware-ray-tracing GPU, for example AMD Radeon RX 5700 XT.
- Install the latest Fortnite version, v40.x or newer.
- Launch Fortnite using DirectX 12 rendering mode.
- Open Fortnite graphics settings.
- Enable Nanite / Virtualized Geometry if available.
- Check the Global Illumination and Reflections settings.
- Observe that Lumen GI and Lumen Reflections are not available / not selectable.
- Observe that the game displays: “Ray Tracing is not supported on this platform.”
- Check the Fortnite log file after entering the Athena / Battle Royale frontend.
- 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:
- fall back to Software Lumen / software ray tracing where supported by UE, or
- 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