Since UE4.19 (at least) my landscape displays awful “popping” where, when moving towards a landscape, a part of the mesh briefly down-rezzes then soon reverts that resolution right back, correcting the mistaken down-res. The effect is that an area of the landscape in view suddenly deforms then pops right back to the way it was. This is constantly happening during movement - one area pops, then another area pops; the whole landscape writhes if you move fast enough.
Watching at high quality helps because the landscape jumping around can look like video compression artifacts. Watch how the crests of the dunes in the distance are dancing around:
The video compression makes it harder to follow the wireframe section at the end, but you can see that as you approach, chunks of mesh erroneously switch down a LOD then pop back. This is with the landscape LOD settings left at default.
If you stop moving towards the area mid-pop, it stays down-rezed, so it’s distance-based LOD at fault (well, screen-based). Likewise the problem stops if I force LOD off with console command “r.forcelod 0” or by cranking up the Landscape’s Details > LOD Distribution > LOD 0 = 5
Something has gone wrong because when you go BACKWARDS, the same thing happens - first it down-rezzes, then it pops back, and if LOD were working as intended, surely it would stay down-rezzed as you move further away, and likewise, when heading towards it surely it shouldn’t down-res as you get closer?
I’ve done some searching but haven’t found any reference to this behavior, is it a Thing? Am I missing something? Am I doing something stupid? Thanks!
UPDATE: This problem happens when the camera FOV exceeds 90. If I change the camera I can get it to stop. I believe it’s older than 4.19 and it still occurs as of 4.23 (the latest version at time of writing).
There’s a bug in the tracker now, and you can vote there to indicate the bug matters to you: