The issue: Since upgrading to version 4.11 I have encountered a problem with Gaussian DOF producing black flickering squares all over the screen on play. I have found the cause of the problem to be particle lights in the flaming torches of my scene (pretty much the same as one of the flame particle systems from the free infinity blade assets), specifically caused by having the radius scale setting set to any number above 20. In 4.10 I had the radius scale set to the previous default of that particle, 500 with no issues. The issue also isn’t specific to my hardware as it happens on two vastly different PC’s.
Update:
The flickering occurs in 4.11, most clearly when using depth of field and either FXAA or AA set to none.
Temporal AA reduces the flickering greatly to tiny black squares that flicker.
Turning off depth of field in 4.11 also produces the same tiny black square issue, regardless of your AA method
Depth of field seems to act as an amplifier that makes the squares huge.
Build type: Unreal Launcher
Build version: 4.11.2-2946394
Asset for issue replication: The issue occurs with “P_Env_Fire_Grate_01” from the free infinity blade effects pack.
Any tips on resolving this issue (without getting rid of the particle lights) would be greatly appreciated, although it appears that this is a bug in 4.11.
Video with examples of all scenarios: [- YouTube][1]
I am not getting this with P_Env_Fire_Grate_01 or any other assets with Particle Lights. Can you send me your dxdiag info so I can see what hardware you’re running on?
Hey , i’ve supplied dxdiag for two machines as it doesn’t seem to be linked to just the one.
I’ve also done some more testing, trying to replicate the flickering issue.
For some reason I haven’t been able to trigger it in a blank project with infinity blade assets added, but I have been able to get it in a content examples project. This may mean there is a conflict with particle lights and one of the project settings.
Here are the steps I’ve taken to reproduce the issue:
Created a new content examples project v4.10 (because you can’t add the infinity blade effects pack to 4.11)
Added the infinity blade assets to the 4.10 project
Added ‘P_Env_Fire_Grate_01’ to the middle of the ‘ExampleProjectWelcome’ scene (no issues)
Upgraded a copy of the project to 4.11.2
Open the 4.11.2 project and go into ‘Global PostProcess’ in the ‘ExampleProjectWelcome’ scene, and change the AA Method to FXAA or None.
Immediately see issues in the ‘ExampleProjectWelcome’ scene. Flashing lights (caused when using bokehDOF)
Change DOF type in ‘Global PostProcess’ to Gaussian, which then causes the large black squares to flicker over the screen.
This is a good example of the issue. If you go one step further you can still see tiny black pixels flickering on the ground if you remove DOF and change your AA back to Temporal. It looks like the same flickering issue but on a much smaller, harder to see scale. Definitely appears to be some sort of bug and conflict with particle lights and some other setting in 4.11.
Thanks for looking into this! I’ve been struggling to find a way around it.
