What may be causing this "tile" effect on navmesh?

[Ares9323]

I’m working in UE 5.7 and it’s the first time I encounter this issue, the navmesh generates many squares and I don’t understand the reason why. Any idea?

[BRGEzedeRocco]

Hello @Ares9323 ,
You could try the following.
First, increase the Tile Size UU. Another thing you can try is adjusting the Cell Size and Cell Height values. In many cases, tweaking these settings helps resolve NavMesh generation issues like the one shown in your screenshot.

Then rebuild the NavMesh by going to Build - Build Paths.

I’ll also leave a few posts below that mention the solutions I described above, as they might be helpful for reference.

How to get nav mesh bounds volumes covering the whole surface on a tile map ?

Hi everyone ! I am trying to make a quick prototype of a 2D top down game. I use a tile map, and I set a nav mesh bounds volume on it to allow my AI character to move to some locations in the map. My issue is the nav mesh bounds volume does not cover all the area where the character is supposed to move on. Now I will try to give more details to provide a better explanation of what I have done: I am using UE 5.2.1 My tile map is on the XY plan, the Z vector is the normal vector of the tile m…

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I’m hoping someone can help me out with this. I’m setting up a modular building system that allows the user to place static meshes into the game and have an AI use a newly placed item to walk around the level. My particular issue is with stairs. When I place some stairs into my level the Nav Mesh rebuilds itself and looks like it should work but I notice a “seam” between some of the levels. Occasionally it’s just on the first instance of the placement and from there the AI will move just fine, b…

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I am experiencing the issue that my NavMesh tiles leave big gaps. Sometimes the path finding is not able to make a path across these and it’s searching another way around it. The tiles size doesn’t seem to make anything better. I found out that the “Agent Max Step height” can drastically reduce the gap, but my pawn isn’t able to get over steps which are bigger than 10 cm. These gaps are happening primarly on uneven surfaces. How can I reduce these gaps or make them disappear completely? [33919…

Hope it helps!

[Ares9323]

Thanks for your detailed answer, increasing the tile size makes it less noticeable but it’s still visible on tiles edges. Aren’t larger tiles less performant if you are using real-time navmesh generation? (I guess it has to recalculate a bigger area, and if I pass from 1000 to 4000 the surface becomes 16 times the initial…

[James.Keeling]

You are correct that larger tiles are more expensive to rebuild at runtime. They do save on memory overhead though which makes tile size a tradeoff.

The issue in your screenshots appears to be a visual issue with how the navmesh debug proxy draws the tiles. I have seen other reports with similar problems, but they are usually only visual and paths (check this with two Navigation Testing Actors) cross through the “seams/breaks”. A navmesh edge should show as a thick dark green line around the cutout in the navmesh and not just a missing section.

There has been some issue if the edges of the two tiles are slightly too large to connect due to the imprecision of the voxelization. That case can be solved with smaller cell size and height.

I would also recommend using Chunky Monotone for both layer and region partitioning. The default has been watershed for as long as I remember, but it is something i encourage many people to swap out of using. This helps with the issue you are seeing as well.

-James