White pixel flickering artifacts with "DitherFade" material layer about cesium-unreal HOT 3 CLOSED

I noticed an interesting comment in "Dither Temporal AA"...

So I tried something silly by inverting the fade percentage (using a 1 - x node) ... and it weirdly works? The tilesets no longer flicker at the highest level of detail! This is true regardless of whether Enable LOD Transitions is true.

For the acutal transitions, I can't tell the difference between the previous implementation and mine. But maybe I've been staring at this for too long. 😅

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Sounds very much like,
#1359

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Trying to do some experimentation to resolve this issue. I made some test modifications to our ML_DitherFade Blueprint.

From what I understand, the "Fade Percentage" seems to roughly translate to the intended opacity of the tile, or the amount that the tile has faded in. I noticed that even when the Fade Percentage is 1.0, it still goes through the "Dither Temporal AA" block, which causes the flickering. Indeed when I hardcode the opacity mask to be 1.0, that flickering goes away.

So with that in mind, I tried to catch when the percentage is 1.0. If it is, I hardcode the opacity mask to 1.0

This does remove the flickering at the highest level of detail. But unfortunately, it impacts the transitions themselves, making them look a lot less smooth. (Between multiple levels of detail you can see clear "jumps" where that percentage is 1.0).

So I don't know what the fix is 😅 Ideally, that "Dither Temporal AA" block wouldn't apply dithering if the fade percentage was zero. I'll keep digging

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