II’m experiencing a rendering artifact in UE 5.7 that I can’t resolve. Setup: Substrate material with Clear Coat layer Lumen Hardware Ray Tracing reflections enabled “Max Roughness to Trace” set to anything other than 0.2 (e.g., 0.4, 0.6, 0.8) Issue: A small colorfill square / tile art…

Hi ! I happen to have the same exact issue but i didn’t dig in as deep as you did. I did find that Max roughness to trace changed it and i do have HWRT and substrate so we must experience the exact same issue. As for a solution, well it’s in fact pretty easy to overcome ! I use 5% overscan and tha…

Experiencing the exact same thing. Let’s hope this gets fixed for 5.8. [image] Substrate Automotive - Coated materials produce NaN/bad pixel Rendering The substrate automotive materials produce a NaN/bad pixel in the top left corner, when using any multi coate…

Hi Allan. I had the same issue, I have the “same” setup that you have too. What I found that worked for me was actually to add / remove a CVAR. r.Lumen.Reflections.maxRoughnessToTrace -1 This took away the entire bug for me and I will flag this to Epic as well. I really hope this helps you out, le…

UE 5.7 – Substrate + Clear Coat + Lumen HWRT causes colorfill square artifact

Development Rendering

The_Distiller (The_Distiller) April 19, 2026, 3:02pm 3

Experiencing the exact same thing. Let’s hope this gets fixed for 5.8.