Terrain HLODs generating with dark outlines

FajkPes_YT
Sat, 21 Mar 2026 19:00:47 +0000
Issues and Bug Reporting

Summary

When I generate HLODs for landscape proxies that are set to spatially loaded (to save memory during the game), the generated HLODs will now have dark outlines around the edges of each HLOD section and I can’t do anything about it to fix it.

It looks like the base texture of each landscape HLOD is generated/captured incorrectly and has these grid-like black lines on its sides.

This started happening after the UEFN 40.00 update.

1. My guess is that the HLOD builder now can’t handle different landscape proxy sizes or resolutions correctly.
If somebody tested it and it generated perfectly fine for them without the black outlines, it might be because I have different landscape proxy sizes on my map. So the base texture (and maybe other textures of that terrain HLOD) is generated/captured incorrectly or with bad scale. Or maybe the HLOD Builder just added these lines on top of the generated base color after the generation ended for some reason I don’t know.

2. Secondly, I found an interesting thing in the patch notes: it says that the engine now computes two different landscapes next to each other differently when placing a spline, because it was off by one pixel. That fix might be affecting terrain HLOD generation, because if you generate a 1024× terrain HLOD texture, the black line is nearly one pixel wide. But I could be completly wrong

I can’t publish my map now without these HLODs so I will be waiting. I hope it will be fixed soon. Thank you!

Please select what you are reporting on:

Unreal Editor for Fortnite

What Type of Bug are you experiencing?

World Building

Steps to Reproduce

1. Create a landscape proxies with different sizes or resolution.

2. Set them to spatially loaded on.

3. Generate HLODs for them.

4. Check the generated terrain HLODs – You shloud see black outlines on the edges, maybe only on some of them.

Expected Result

HLODs of Landscapes sections should be clean, without any black outlines on the edges. Just a correct texture of that part of the terrain in lower resolution that seamlessly connects to another HLOD landscape section.

Observed Result

Generated HLODs of Landscape sections have black outlines on the edges. They do not seamlessly connect to other HLOD sections, especially if you’re generating low resolutions terrain HLODs textures to save memory.

Platform(s)

PC

Island Code

3219-2663-0382

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Additional Notes

It’s affecting only HLODs of terrain
I can’t fix it by myself because in UEFN every Landscape HLOD Generation setting outside of source LOD and Texture size is locked. Even if you have Advanced HLOD setting enabled in editor settings.

The only “somewhat” workaround I found is to generate terrain HLOD with a very high resolution, like 1024x1024 pixels instead of my usual 128x128. But this makes the project size huge, slows down cooking times and totally ruins the point to lower memory usage on my map. And also it makes the game download so large, because its so much texture data and textues now take so much memory.
I have 200 terrain proxies on my map and I can’t afford for each terrain HLOD section to have such a large textures. That’s 3 textures times 200 and every texture has 1024x1024 pixels.

9 posts - 6 participants