4.25 anti-aliasing problems

After migrating a simple project from 4.24.3 to 4.25 I see a number of problems with flashing of light on textures. This is on a 4k system with RTX 2080.

In 4.25, if I set the anti-aliasing to TemporalAA then the flashing stops (but this shows a different problem). For ‘none’ or the other two modes of AA there is the flashing problem. Also the light intensity looks 50% more than what is was in 4.24.

In terms of the light intensity, there is a setting ‘Auto Exposure Bias’ which seems to be set to 1.0 by default in my 4.25 converted project. This is affecting the overall light intensity, even though Auto Exposure is unchecked. I set this down to 0.5 and it looks more like 4.24.3 now. But only TemporalAA works without flashing on textures. For me FXAA produced sharper images even though they were still blurry. TemporalAA is very blurry (unless you add in a post processing sharping material - which doesn’t seem right as it would reduce the overall fidelity).

Textures are flashing/flickering between first and second picture (for example) multiple times within a second. The second image, without the white, was how it looked in 4.24.3 (without flickering). This is happening on many different textures including Belica paragon character. It also happens even if there is no light source and just a water plane.

With TemporalAA there is also a problem showing up along the seams of textures. It shows up as flickering white specks. See last picture.

All this makes 4.25 unable for me. Not sure why I’m the only one seeing this. It’s a simple project with one light source with no post processing.

Take a look at this post to see if it’s at least part of the issue. The fix is in the last reply.

Okay thanks, yes that could be it. I pretty much went back to 4.24.3 for now and uninstalled 4.25 and removed my migrated project, so, I’d likely wait until a 4.25.x (or 5…) and see what the state of things are.


****** HERE’S FLICKERING FIX *********************

Official 4.25 and 4.26 having some glitches in calculations, namely TemporalAAHistory structure was not filled out correctly

Here’s the only solution that will surely fix for both 4.25 and 4.26 versions (building from the source and fixing engine glitch), since 4.25 will not have any more updates and 4.26 also has the same issue:

  1. get Unreal 4.25 source, following link is a step by step instructions on how to get the source (no need for the building until you change buggy scripts, just when you get 4.25 source unzipped from git, run Setup.bat, after that **run GenerateProjectFiles.bat **): Building Unreal Engine 4 (UE4) From Source Code / GitHub - YouTube

  2. **change this 2 scripts **as explained in the below link, and finally, **build the source **…48f5a38dfb53ea

  3. compile your project from source (in the following link, instructions are around 8.50 min): Building Unreal Engine 4 (UE4) From Source Code / GitHub - YouTube

Enjoy again your UE4.25/26