I need Help with the Nav Mesh Bound Volume

[seb-barr (naos_dealer)]

Hello there, I am a UE5 beginner I’m having trouble with my project that I just can’t seem to figure out how to solve.

I’ll try to be as clear as I can (a little bit tricky). Here is my issue:

When a new game is launched, the main map is loaded. Within the level blueprint of this main level, there are 3 other sub-levels loaded with the node EventBeginPlay and then Load Level Instance by Name (see the screenshot). The point is to create random parts of the main level. In those sub-levels, there are enemies to kill and puzzles to solve.

However, the enemies don’t move around and don’t attack the player in those sub-levels (when the main map is loaded).

I understood that the problem comes from the Nav Mesh Bound Volume, which doesn’t load properly in those sections, for some reason.

I tried different things like putting only one huge Nav Mesh Bound Volume in the main level and NOT within the sub-levels, or the other way around, but nothing really worked. The Nav Mesh Bound Volume of the sub-levels just doesn’t load correctly.

I would be very grateful if you guys could help me solve this problem. I haven’t found the solutions in this forum or on YouTube.

[Leomerya12]

Hello,

There could be the possibility that, during gameplay, it is being deactivated. You can have the NAVMESH persist to debug it during gameplay with this command:

Is it possible to view my NavMesh in PIE?

To have the change persist, type this in the command console ShowFlag.Navigation = 1

[seb-barr (naos_dealer)]

Yes absolutely, the NavMesh of the sub-levels seems deactivated when I open the Main level, perhaps it’s due to the node load level instance. Is there a way to force it to open ?
Thank you so much for your help, I really appreciate it

[Leomerya12]

Make sure to hit “REPLY” because it’s luck that I saw that you gave a response.

Could you post a video so I can see what is happening?

[seb-barr (naos_dealer)]

@Is it possible to view my NavMesh in PIE?

ShowFlag.Navigation = 1

Yes I make a video to show you.

Really sorry if my explanations are not clear, it’s kind of hard to explain and english is not my native language, obviously

Aletheia_for_forums.unrealengine

I’ll take any suggestion, thank you again

[Leomerya12]

Ah, okay, that makes things much easier for me to understand!

Thank you.

So, you said it’s a “SUB-LEVEL”, so what I think is happening is that your NAVMESH is not in a PERSISTENT level.

Open the LEVEL WINDOW to see what I mean:

[seb-barr (naos_dealer)]

What I call a “sub-level” is a level loaded within the main map, maybe the termynology is confusing, sorry about that

I’m not sure about the NAV Mesh, seems to be right, isn’t ?

[Leomerya12]

Understood!

There’s a few things you can try:

Change “Should Discard Sub Level Nav Data” from TRUE to FALSE (Mine is set to TRUE).

Also, make sure this is set to DYNAMIC and not STATIC:

[seb-barr (naos_dealer)]

It worked !!! The Runtime generation parameter (dynamic) solved the problem. The only slight downside: this change drastically lowered the FPS. I had to resize the NAV Mesh and optimize its location to increase the FPS. It’s not perfect (around 60fps) but it’s working !

If anyone else finds themselves in this situation, here’s what to do: delete all the Nav Mesh from the “sub-levels” and add one in the main map, and make sure the Runtime Generation is set on dynamic.

Huge thanks to @Leomerya12 , you solved a problem I had been struggling for weeks. I owe you a coffee ;