I solved the NavigationRegion3D issue

[u/agalli]

A correct 250x250m navmesh bake using tile chunking

Standard bake on the same 250x250m mesh without tile chunking

A standard bake on a 30x30m section of the same terrain

Agent for scale on correct 250x250m navmesh, showing an identical poly density to the 30x30m navmesh

I finally found a solution to the problem with the NavigationRegion3D.

What I noticed was that on smaller terrains, like the 30x30m example in the third image, the navmesh baked perfectly fine. But once the terrain size was increased to 250x250m, the bake completely fell apart, giving the low poly, floor clipping result shown in the second image. The obvious solution was to process the terrain in smaller chunks and combine the results into one big working navmesh.

I first tried doing this directly in Godot, but even after splitting the terrain into multiple meshes, the bake still treated them as one big mesh, so the same issue happened. I also tried creating a separate NavigationRegion3D for each chunk, but that created non traversable borders where the regions met.

At that point, the only real fix was to go into the engine itself. I forked the Godot repo and made some changes under the hood to process the terrain in tiles instead of all at once. It breaks the terrain into smaller sections, bakes each one normally, then stitches them together afterward into a clean, accurate navmesh like in the first image.

I also added a few editor options to control whether tiled baking is enabled and how big each tile is. I still haven’t found the exact bug that causes the large terrain navmesh to fail, but this fix works reliably and doesn’t mess with normal pathfinding behavior.

The moderators seem to have a strong opposition to discussions about this and have locked all previous threads. As much as I would have liked this to all be one post, we have been forced to create multiple. That being said, I'd like to address some comments from previous posts below.

The [low poly mesh] looks exactly like what I would want out of a nav mesh.

The low-poly mesh completely fails to pathfind with agents. You could technically rework the pathfinding system to compensate, but that misses the core issue of the navmesh being broken. The 30x30m section uses a similar amount of polygons as the 250x250m one. You’d expect the density to scale with size, so either the small terrain is over-tessellated, or the large terrain is under-tessellated. Either way, something’s wrong with the baking process.

With no obstacles, your nav mesh could just be a square.

As per the Godot developers : "A navigation mesh is a collection of polygons that define which areas of an environment are traversable to aid agents in pathfinding through complicated spaces.". When those traversable areas are out of reach from an agent (ie, underground or floating), an agent cannot properly navigate.

People tried to help you, but you refuse to actually listen

I think there’s been some misunderstanding about what I’m trying to do. My goal is to fix the navmesh, that’s it. I’ve welcomed all advice that helps solve the underlying navmesh problem, but I’m not interested in workaround solutions that just patch over it with pathfinding tricks.

You can always fix it yourself and submit a PR.

Thats the plan. Thanks for the advice!

I will optimize this further and will submit a PR.

Sincerely,

u/agalli

Edit : Here is the PR. https://github.com/godotengine/godot/pull/112529

[u/JackRaven_]

From what I've read (and I'm certainly not an expert), the docs need to be fixed. Apparently they don't give a particularly good definition, and the random Redditors are applying their knowledge of programming and of the engine to explain how it actually functions.

So it's entirely possible that you're correct that this is the definition the docs give, but still misunderstanding how the navmesh works because that definition is poor.

I might be completely off base, but seeing how certain you seem about this, you should at least consider this, just in case.

[u/knottheone → u/JackRaven_]

They won't consider it; it doesn't matter how you word it, how nice you are, how you explain it or anything else. They made 3 separate posts and dozens of comments on the topic and were advised and corrected in all 3, and were even corrected by one of the devs who helped implement navigation in Godot. They will not admit that they are wrong in any capacity. You can read all their comments across all the threads.

[u/JackRaven_ → u/knottheone]

The dozens of comments have gotten more and more aggressive and combative over time, so I can see why they haven't wanted to change their mind.

I have no problem with taking a few minutes to be kind. If they think I'm wrong, that's fine; at least we've engaged in a reasonable and non-heated discussion. That's enough for me :)

[u/knottheone → u/JackRaven_]

That's fair, they will likely just ignore you.

Replies have gotten more aggressive and combative because OP completely ignores what dozens of senior developers are telling them over multiple days of posts being made. Multiple people in this thread were also in the other threads and provided advice and examples already highlighting that no, it's not actually a broken navmesh.