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Effect of r.LandscapeLODDistributionScale on Temporal Antialiasing Upsampler - Bug or Feature?

Hello all,

I’ve been experimenting with TAAU quite a lot just recently via Engine.ini tweaks in Milestone’s RIDE 4 game and stumbled across an interesting finding. I’m not sure if my lack of understanding is the problem or if I’ve found something genuinely interesting and useful, so here goes.

First, the basics that I do understand. Adding the following to Engine.ini gives me TAAU with, I believe, the PS5 algorithm with a view port of 2560x1440. By the way, I’m running the game at an output resolution of 2160p. This gives my mildly overclocked Sapphire PULSE RX Vega 56 the legs to hold a locked 60FPS nearly all of the time in first-person view with the highest in-game graphics settings.


[/script/engine.renderersettings]
r.SecondaryScreenPercentage.GameViewport=66.66
r.TemporalAA.Algorithm=1
r.TemporalAA.Upsampling=1

The rest of the script is included below for clarity showing tweaks to increase AA sharpness a little, fix a few LOD issues, and to help with texture loading as well as a few basic rendering quality tweaks.


r.TemporalAASamples=8
r.TemporalAACurrentFrameWeight=0.1
r.SkeletalMeshLODBias=-2
r.LandscapeLODBias=-1
r.LandscapeLODDistributionScale=2
r.MipMapLODBias=-1
foliage.LODDistanceScale=1.67
r.StaticMeshLODDistanceScale=0.6
r.ViewDistanceScale=1.67
r.Streaming.MipBias=0
r.Streaming.AmortizeCPUToGPUCopy=0
r.Streaming.MaxNumTexturesToStreamPerFrame=0
r.Streaming.Boost=1
r.Streaming.LimitPoolSizeToVRAM=0
r.Streaming.PoolSize=3000
r.Streaming.MaxEffectiveScreenSize=0
r.SSR.Quality=3
r.PostProcessAAQuality=5
r.MotionBlurQuality=0
r.LensFlareQuality=0

Notice the inclusion of *r.LandscapeLODDistributionScale=2. *Initially, I was totally unaware of this until stumbling across it almost by accident on another forum in a conversation that had nothing to do with TAAU, so it’s a miracle I even bothered trying it.

Without it, TAAU appears very soft as though the entire image has been passed through a moderately heavy blur filter, and none of the usual sharpening methods offered by UE4 help with this one iota. Some even seem to make matters slightly worse.

With it, antialiasing quality benefits dramatically (almost like someone adding MSAAx4 on top of TAA in some ways), and image detail everywhere improves by what, subjectively at least, I’d consider to be a factor of 4.

Visually, the positive effects of using this are enormous in this particular case with close to zero impact on performance.

So, should I have been using this all along, or have I discovered something new and unusual?

I’m unable to upload sample screenshots to the forum, so here are Google Drive links to:

Without… https://drive.google.com/file/d/19-P…ew?usp=sharing

With… https://drive.google.com/file/d/1vPH…ew?usp=sharing

If you view them fullscreen on a 4K monitor, the difference is very clear.