When rendering a game in splitscreen using Lumen HWRT, Nanite and a large number of Niagara Mesh Particles 1mil+, various meshes and actors will stop rendering. Setting r.RayTracing.Geometry.NiagaraMeshes=0 and running the game resolves the issue. No warnings or errors are shown in the log or on screen.
Enable lumen reflections with hardware raytracing in a scene with a lot of nanite meshes and start a splitscreen game (see attached project for repro)
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-380600 in the post.
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| Component | UE - Rendering - Graphics Features - Ray Tracing |
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| Affects Versions | 5.7, 5.8 |
| Target Fix | 5.8 |
| Fix Commit | 54263913 |
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| Created | May 20, 2026 |
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| Resolved | May 20, 2026 |
| Updated | Jun 22, 2026 |