Quick answer: “Flickering” has several different causes. Find out which one you have first, then fix that.
- Two surfaces swap back and forth in stripes or patches: that’s Z-fighting. Move one surface slightly or delete the duplicate.
- The whole screen gets brighter and darker as you turn: that’s auto exposure. Lock it in a Post Process Volume.
- Only the shadows or the bounced light crawl and boil: that’s Virtual Shadow Maps or Lumen.
- Thin edges, fences and foliage sparkle: that’s aliasing. Check that the Anti-Aliasing Method is TSR and the screen percentage is 100.
Which kind of flicker do you have?
| What you see | Usual cause | Fix |
|---|---|---|
| Two surfaces fight, with stripes that change as the camera moves | Z-fighting: two surfaces at the same depth | Z-fighting fix |
| The whole image gets brighter and darker | Auto exposure (eye adaptation) | Auto exposure fix |
| Bounce light and dark corners boil or form blotches | Lumen noise | Lumen fixes |
| Shadows flicker, look blocky or vanish | Shadow page pool full, or swaying foliage | Shadows section below |
| Thin lines, fences and leaf edges sparkle | Aliasing on details smaller than a pixel | Anti-aliasing guide |
| Moving objects leave trails | TSR or TAA ghosting | TSR ghosting fix |
| Glass, water or particles pop in front of each other | Translucency sort order | Translucency section below |
Step 1: Turn things off until the flicker stops
Switch off one thing at a time. Whatever you switched off last is the cause.
- In the viewport, open the Lit menu and pick Unlit. Still flickering? The cause is geometry (Z-fighting) or a material, not lighting.
- Pick Lighting Only. Flickering only here? It’s lighting: shadows or Lumen.
- Go back to Lit, then open Show > Post Processing and untick Eye Adaptation. If it stops, it’s auto exposure.
- Type this in the console (the Cmd box at the bottom of the editor). If the image turns jagged but steady, anti-aliasing was the source of the flicker.
r.AntiAliasingMethod 0
Set it back afterwards with r.AntiAliasingMethod 4 (TSR).
Shadows flicker or look blocky
UE5 uses Virtual Shadow Maps. In big scenes with a lot of foliage, they can run out of memory pages. Shadows then flicker or go missing, and the editor shows a red warning about the page pool. Raise the limit:
r.Shadow.Virtual.MaxPhysicalPages 4096
Try 8192 if the warning stays. It uses more GPU memory. To keep the setting, add r.Shadow.Virtual.MaxPhysicalPages=4096 under [SystemSettings] in your project’s Config/DefaultEngine.ini.
Foliage that sways in the wind forces its shadows to redraw every frame. On the foliage mesh or foliage type, set World Position Offset Disable Distance so distant plants stop moving.
Glass, water or particles flicker
Unreal sorts translucent objects per object, by their distance to the camera, not per pixel. When two overlap, their order can swap as the camera moves. Select the one that should draw on top and raise Translucency Sort Priority in its Rendering section.
Flicker only in Movie Render Queue renders
TSR and Lumen build up their result over several frames, so the first frames of a shot can flicker. In your Movie Render Queue config, add the Anti-aliasing setting, set Temporal Sample Count to around 8, and raise Engine Warm Up Count. See Get the most out of Movie Render Queue.
FAQ
Why does it flicker in the editor but not in the packaged game?
The editor viewport can use a different screen percentage, scalability level and exposure. Check the viewport’s Screen Percentage and the Lit > Exposure options before you change project settings.
Will a faster GPU fix flickering?
Usually not. Most flickering comes from settings or content. If you see black squares or corruption over the whole screen, update your GPU driver.
Why is flickering worse at low frame rates?
TSR, Lumen and shadow caching all reuse previous frames. At low frame rates the frames are further apart, so they have less to work with and look less stable.