[Engine 5.6] Ghosting and grainy shadows

Bug Reports
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5

Yeah, ghosting is one of Lumen’s core issues, it was insanely bad back when I was participating in the UE5 alpha testing, and Epic has been fixing it painfully slowly through improvements to Temporal Upsampling across versions, but it’s still unresolved.

In UE, ghosting can be reduced by:

  • enabling TSR
    r.TSR.CameraCutRejection 1
    r.TSR.History.GrandReprojection 1
    r.TSR.History.ScreenPercentageWeight 0.5
    r.TSR.History.VelocityWeight 0.9
    r.TSR.ShadingRejection 1
    r.TSR.ShadingRejection.Flickering 1 r.TSR.Velocity.Extrapolation 1
  • lowering Lumen GI quality (Final Gather)
  • lowering Lumen Reflections quality
    OR
  • switching as much as possible to Hardware Ray Tracing instead of Lumen’s software ray tracing pipeline.

I think it’s worth exposing a dedicated settings section for owners of high‑end GPUs (4080/S, 4090, 5070Ti–5090) with a large number of RT cores, it’s a niche solution, but a very promising one.