TAA - The Problem with UE5 and Modern Gaming
Greetings, fellow adventurers!
As we are approaching closer to the release of the Alpha 2 (copium), I have come across a peculiar but rather unavoidable thought regarding the graphical quality of the game.
In the past, games used to use AA solutions different from today. Today, the most widespread AA technique, and the most performance-friendly is probably TAA, which is also used for DLSS and, as far as I know, FSR and other upscaling methods.
TAA brings performance-friendly AA solutions to the table (for reference, TAA means Temporal Anti-Aliasing). I won't bother everyone with how TAA works or why it works like it does. What I want to bother everyone with is how it looks visually.
Due to how TAA works, it has a very powerful negative effect on the experience of the majority of players, this negative effect is called blur.
In short, TAA permanently introduces a blur effect to the image. As a real life example, someone who needs glasses to see well can perfectly understand the blur I speak of.
For example you look at a tree, and you take your glasses off, and something is off, the tree looks blurry, without detail, you can't quite focus on it properly. You put your glasses on and voilla, the tree looks lovely, with details and you can properly focus on it.
This is basically what TAA does to a game, it "blurs" together frames to eliminate aliasing. Good examples can be seen in Red Dead Redemption 2 and the Black Myth Wukong benchmark tool available for free on steam.
Enter: The Solution
There are 2 main solutions to TAA from the perspective of the player, both are brute-force. Higher resolutions reduce the blur effects of TAA. In fact, higher PPI brute-forces TAA into looking clear and sharp.
Of course, only the top most expensive gaming rigs can even run the high resolution required for TAA to look good. You either use a 1440p screen to brute-force a 4K image with the use of super resolution tech (such as DLDSR) or you outright use a 4K native screen.
Most people use 1080p, 57% in fact going by the steam results, while 20% use 1440p, only 3.6% of gamers use 4K and for good reason. 4K looks great, but is extremely difficult to run.
From the perspective of the developer, TAA can be optimized so that, put frankly, it doesn't make the game look like a smeared mess of blur where you can't make out details farther away than 2 meters in front of your character. I will give again the example of Black Myth Wukong which even at 4K does not look great, and it's the same UE5 engine Ashes will run on, the difference being different optimizations as we're talking different games.
I'm writing this post more or less to bring it to the attention of the developers in case they don't already know of the issues that TAA implements. If possible, I would check with a native 1080p and 1440p screen to make sure the game looks acceptable at those resolutions, this is because, again, TAA negatively impacts player experience the most at 1080p and 1440p. I don't want the game to end up being a shimmery, smeary, blurry mess due to this blessing-curse we have that is called TAA.
(Note that disabling TAA as the player more often than not breaks game engines entirely and makes the aliasing explode into a shimmery mess, so you can't just disable it and use FXAA or MSAA or other methods. Also, DLSS and DLAA use TAA to work well, so they don't disable it either as far as I know).
All in all, TAA is an amazing solution for performance-friendly AA, but if optimized poorly or wrong it can destroy the experience entirely, so it's the most double-edged sword of AA solutions there is atm, as far as I know at least.
For players interested in how TAA behaves visually, I urge you to try out the free Black Myth Wukong benchmark tool from Steam at 1080p and 1440p. If you happen to notice even at max settings that the image looks off or blurry, that's because of how TAA works. Tbh, 4K does not fare much better either in this test so it's rather extreme but a good example nonetheless.
