World Partition - wrongly lit patches

[FFV-LM]

Hi there, I’m struggling with a weird glitch using world partition. It goes away if I open the landscape tool but is still there when running or rendering via MRQ.

Has anyone an idea what could cause that?

Thanks in advance!

Lukas

[brs-sebascova]

Hello there @FFV-LM!

Since those patches dissapear when opening the landscape tool, yet remain on screen when rendering, it sounds like you are seeing HLOD proxies on screen, instead of the landscape itself. And if those HLODs were created before you made any changes to landscape or lights, then they will hold old data, resulting in the glitches you see.

To confirm this, use cmdlet r.HLOD 0, and check the screen. If the strange patches are gone, then it’s a HLOD issue, and to solve, you can just rebuild your HLODs by going to Build > Build HLODs. That will create new proxies for your land/light setup.

On the other hand, if the glitches remain in sight, I would test by rebuilding the landscape’s Nanite data:

For further tests, I would check the methods in the related thread below:

Distant Landscape Material Black when using World Partition HLODs

Hi, I was attempting to setup World Partition loading for my landscape, but I’ve ran into an error where distant HLODs render black in-game. I spent a few days searching forum posts and trying different settings to narrow down the problem, but I haven’t had much luck. It’s hard to find information on World Partitions, so some help solving this would really be appreciated. Here’s a comparison of what I can see in the editor, and when the game is running: [Screenshot 2024-10-03…

[FFV-LM]

@brs-sebascova

r.HLOD 0

Hey there, thanks for you quick answer!

Disabling HLODs doesn’t show any change. I’ve enabled and build the landscape’s Nanite data which also didn’t do anything but once I’ve disabled Nanite again, it looked normal. Unfortunately this only lasts until I save the LandscapeStreamingProxies, once that’s done it’s back to the weird patches again

[brs-sebascova]

Hello again!

Interesting, the landscape works as intended without Nanite, then breaks when you save the proxies. That suggests we could be dealing with a cache conflict, which would make sense after multiple changes and rebuilds.

To clear out the cache, close UE, navigate to your project’s main directory, and delete folders Saved, Intermediate and DerivedDataCache. After that, go to Unreal’s app data folder (usually at AppData\Local\UnrealEngine\Common\), and delete the DerivedDataCache folder from there as well. Now, re-open your project, and allow it to rebuild it’s cache.

If the issue remains active after that, then please test the following:

• Try to sync Nanite data across all proxies, by opening the World Partition window, loading all regions/cells, enabling Nanite, and building data from there. After that, save the project

• This is a bit of a reach, but if the project is using Virtual Shadow Maps, there’s a chance that the shadow data is in conflict with the proxies. To check that, use cmdletr.Shadow.Virtual.Cache 0to temporary disable the VSM cache