[BUG?] Adding water body forces all World Partition cells to display, that raises "Out of video memory" crash

Steps to reproduce
0. Essential computer components: GeForce RTX 4090, Intel Core i9-12900K, 64 GB RAM + 128 GB swap, SSD.

  1. Create a new blank project with starter content.
  2. Enable Water and Landmass plugins and restart the project.
  3. Create a new “Empty Open World” level.
  4. Create landscape with parameters: Enable Edit Layers - true, World Partition Grid Size - 8, Material - M_Ground_Grass (this in why the starter content is necessary), Location - (0,0,0), Section Size - 255x255, Sections Per Component - 1x1, Number of Components - 32x32.
  5. In landscape manager, go to Manage - Add, set brush size to 32 and add 32x8 components rectangle on each size (the landscape will have a shape of very rough “circle”).
  6. In the World Partition window, unload most of the cells (leaving a quarter will show the bug brightly).
  7. In the Place Actors panel, go to All Classes and add some water body to the landscape.
  8. Save and reopen the level.
    Actual result
    The entire landscape is loaded and you cannot unload parts of it. If you don’t have VERY MUCH video memory, the engine will crash in several seconds.
    Expected result
    The landscape must support loading and unloading individual World Partition cells as it is done without the water.
    Screenshot and logs

    MyProject-backup-2023.10.24-22.43.22.log (281.1 KB)
    I have published this using the bug submission form, but there was no reaction to that, the bug had not even appeared in the list and is not being found. Please pay attention for this.

I have just downloaded the latest Unreal Engine version, and I am now seeing that you increased the maximum size of the landscape but did not fix this bug. The topic is actual, can you answer?
EDIT: and the Issues Tracker still does not show any information about this bug. The request was sent 15 days ago. Can you react to this?

Double bump, the topic is actual!

Triple bump.

1 Like

i am also having this same issue

is any support gonna look at this?

Quadruple bump.

I am experiencing the same issue, not fixed by 5.4. Any time I add a body of water, I am unable to unload any cells of world partition. It still runs, but slow.

@Amanda.Schade @SkyeEden @Stephen_Ellis etc., could you please pay attention for this?

Im having the same bug!!! I thought it’s gonna be fixed in 5.4 , but no. This is a crucial thing, without this working the water plugin is useless

@SupportiveEntity, are the pings in the #9 not working? Those users do not respond for the requests? So can you pay attention for this? Can you clarify is this an engine bug, or am I doing something wrong?

Hey there @Etyuhibosecyu! I personally receive hundreds of notifications from around the forums, so I’d assume they would be receiving significantly more. Generally this comes down to an issue with the way the landscape system is built. It seems that when operating on any of the landscape proxies, all of them must be able to be (re)loaded into memory. This can be a problem with larger scale landscapes. That said it does run off of shared memory (both GPU and Shared Memory) so some users have found success in having an absurd amount of RAM and VRAM together, but this is by no means a good workaround. This is a known issue but likely requires a refactor of the landscape system.

@SupportiveEntity, are there any news about this? I do not see this in fixed in 5.4.3.

Hey there @Etyuhibosecyu! I’ve been following PRs involving the landscape systems, and while a couple more fixes are in the pipeline I can’t speak to if they are relevant to this issue specifically.