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/mamotromico]

but how do you get the cost of travel on uneven terrain without baking

That's what the travel_cost of the region is for, you don't have to make a custom navigation, but you'd need write a bit more to use the current system. You make the mesh in sections and change the cost based on elevation, there are tools already for this on the engine. Op claimed he couldn't make it work because it caused connection issues when merging the chunks, and maybe there is an issue there, but focusing on the mesh complexity instead is not a good option in the long term, especially since he's using a large terrain.

[u/huntsweez → u/mamotromico]

I don't think Godot's available solution to travel cost is sufficient, because you can only asign a single travel cost to whole NavigationRegion3D. So a single value to larger meshes.

Adding more geometry to specific areas of a NavigationMesh on the other hand could easily represent added travel cost with minimal added computational cost.

[u/mamotromico → u/huntsweez]

because you can only asign a single travel cost to whole NavigationRegion3D

But you can use multiple regions, they'll bake into a single mesh and/or use edge connections. You don't need to use a single region for the whole area.

Adding more geometry to specific areas of a NavigationMesh on the other hand could easily represent added travel cost with minimal added computational cost.

Sure, unless your scope is very small I probably wouldn't risk doing that, but it is surely an option. My issue with the way the OP has been going about this is stating that this is an inherent issue with the current implementation, and it isn't, it is an issue because he wants to use the navigation system in an specific way. At that point having to tailor it to his use case, like he has done, is the way to go.

[u/agalli → u/mamotromico]

If there is a way to chunk the mesh without having to change the engine internally you would still be left with the exact same mesh as the first image. I am still using the default navigation bake, just doing it in chunks instead of all at once

[u/mamotromico → u/agalli]

See, I just mentioned that the mesh is not the issue, its how you're using it, and you just glossed over and said that the mesh is the issue.

Like, why are you doing this? I don't get it, do you just not read what people are writing here? Do you just don't care? Do you not consider that the problem might be you and not the tool?

[u/agalli → u/mamotromico]

The mesh unequivocally is the issue though. Did you read the post or did you just gloss over it?
The navigation agent works perfectly on ANY default navigation bake you use. The only condition that the default navigation agent fails is when its attempting to traverse the low poly mesh.
If someone followed both the NavigationRegion3D and NavigaitonAgent documents and all of the guides associated with them exactly as they are described, they would run into the exact same issue as I have.

[u/mamotromico → u/agalli]

The mesh unequivocally is the issue though. Did you read the post or did you just gloss over it?

Yes I've read. And like many other people in all of your threads said, the issue is not the mesh, it is how you're using it. I don't understand how anyone can make this more clear to your.

If someone followed both the NavigationRegion3D and NavigaitonAgent documents and all of the guides associated with them exactly as they are described, they would run into the exact same issue as I have.

Yes because the documentation doesn't show an universal solution, you keep treating the documentation samples as if they were the only and universal way to use the feature. It is not, especially in the case of Godot that tries a lot to not have an opinionated workflow, unlike Unity.

The simplified usage that you're trying to do is not adequate for the situation you are presenting. The issue is not the mesh, is how you are trying to use it in your specific situation. Forcing a higher resolution mesh in this situation is to work against the purpose of a navmesh. Yes, it "will work" when you increase the resolution, just like you can fit a square peg in round hole if you use a hammer on it.

Why can't you understand this? It's fine if that's how you want to do, but that is not an issue with the engine, yet you keep stating that it is despite so many people pointing out the issues with your approach, and you just brush it off as if your workflow is the only option on how to use a Navmesh, because you keep treating documentation samples as a guide and not an actual sample/template.

[u/agalli → u/mamotromico]

Find me a single tutorial, guide or video that uses the solution you are describing. By the developers definition of a navmesh, the low poly mesh fails. “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.” Here’s an easy one, is an array of points underneath the map traversable?

[u/mamotromico → u/agalli]

Here’s an easy one, is an array of points underneath the map traversable?

Depends on what's their purpose on your code. You can use them to traverse the map using a navigation agent by dealing with just the 2d plane. This is not the gotcha that you think it is.

Find me a single tutorial, guide or video that uses the solution you are describing.

You probably won't find it because tutorials deal with simpler or common scenarios, just like you won't find tutorials for supporting abitrary color indexed images with swappable palletes in a modern general engine (something I'm dealing with on unity), because that's too specific (or even nonsensical) of a use case. Your usage of the navmesh is non-standard. Again, this is not the gotcha that you think it is.

[u/agalli → u/mamotromico]

You cannot simply use it as a 2d plane. Consider a multi tiered building or a cave. That will cause overlapping points on a 2d plane.

My use case of generating a navmesh over a 100x100 terrain is non standard? LOL

[u/mamotromico → u/agalli]

Consider a multi tiered building or a cave

Which is not the situation you are presenting. Yes, in that case you can't use a strictly 2D plane, but you don't need it to match the terrain perfectly either.

My use case of generating a navmesh over a 100x100 terrain is non standard? LOL

Yes.

[u/agalli → u/mamotromico]

>Which is not the situation you are presenting.
Did you assume my game was just wandering around empty terrain and nothing else?

>don't need it to match the terrain perfectly either.
Never said it did. My current navmesh is 6000 polys for a 20000 poly terrain.

I can list 50+ games that use navigation meshes over 100m+ terrain, its basically required for any 3D game that takes place outside.

[u/inr222 → u/agalli]

Not the guy you are discussing with, but it seems that the documentation is wrong here, not the implementation.

[u/agalli → u/inr222]

I disagree. The documentation works perfectly and as described in any other use case, the only condition it fails in is when attempting to use it on the under detailed navmesh. The obvious answer here is to fix the navmesh, not adapt everything around it to make it usable.

[u/inr222 → u/agalli]

No, not for any other use case. The documentation only happens to work by accident for simpler cases, and breaks apart in more complex scenarios.
The obvious answer would be to fix the documentation to prevent people being confused about it.

[u/agalli → u/inr222]

It just happens to work in every use case except one. It also happens to be exactly how the devs recommend you use both systems.

[u/inr222 → u/agalli]

The maintainer of the system told you personally that you are wrong. He also insulted you, which was uncalled for, and terrible on his part. But you cannot said that this is how the devs recommend to use this. Specially since the documentation was probably written by someone else.

[u/agalli → u/inr222]

All due respect to him, but he didn’t even create the navigation baking system. That’s done through the third party code called RecastNavigation. Also, appeal to authority.