Can't save a levels nav mesh if using world composition?

I’ve recently run into a fairly serious issue. I’ve been trying to figure out how to use world composition to better make a larger world with some parts that can be only loaded in as needed, but I’ve hit a bit of snag.

Every time I try to save a level after having built its navigation mesh, it fails to save. It will show the saving progress bar and all like usual for the level but then once it disappears the level still has the little asterisk on it showing it hasn’t saved, and if opened it wont have any nav mesh.

While testing with different stuff I found out that some levels would save, but then instantly clear their nav mesh and have to rebuild it. This happened with smaller nav meshes, while the larger ones would just seemingly fail to save but not disappear from the cached level I was looking at.
I’ve been looking around a bunch but haven’t found anyone actually mentioning this (though it does seem nav mesh issues with world comp are somewhat common) so I figured I’d mention it here so it can be looked at by somone who may know more than me, or possibly even solved should I just be missing something that isn’t covered in the documentation (nav documentation is overall lacking, and seems completely missing when it comes to its use in world comp levels).

I looked around and tried various things like making the nav mesh in the persistant level or such, but nothing I’ve done has worked.

Hi, I encounter the same issue in 4.18.2. Whenever I press the save icon, it will rebuild the navmesh again and cause the level change to the unsaved state.

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Sadly still no fix figured out. In the end I moved towards having dynamically generated nav meshes, but given the nature of my game and the performance hit is really isn’t ideal and has kind of slowed development to a standstill.

I know this is old, but i wanted to ask what your solution was in the end.
I have a 64 tile landscape. I have tried these things attempting to have a static nav mesh, but have seen some bugs:
option 1:
have a small navmesh bounds in the persistent level, then have individual navmesh bounds in each sub level.
option 2:
just have a large navmesh in the persistent level

Both options “work”, but both options also ask for the navmesh to be rebuilt every time i load the level in the editor. Works if i build it and package it doesn’t complain, it’s just, annoying.

Was wondering what you went with in the end?
I have tried dynamic too, and dynamic with nav invokers and wasn’t too impressed with performance with either…

Thanks :slight_smile:

Never found a fix, I tried dynamic nav mesh generation, but it wasn’t performant enough to handle long ranges of motion, so if the player attacked outside the enemy range, the AI couldn’t find a path to them, and making it bigger was horrible on performance.

It’s now two years later and the project pretty much fell into an indefinite hiatus after that…
Been thinking of trying it again in newer versions of unreal in case that fixed it a few times, but just been more busy lately so… haven’t gotten around to opening the project again for quite awhile sadly.