Navigation Mesh in PIE different than in editor when use NavModifierVolume or and LowHeight area


I have simple NavModifierVolume - it displaying as expected in editor - this is for low area, blue passage on screen:

and here goes same view form PiE:

Rebuild navigation from console, force on load not helps. I even restarted project and it not working in PiE. Maybe it working in full game (like a some other problems), but I can’t work this way - starting full game everytime I need something to test.

In editor it works fine with NavModifierVolume or just with low areas (design). In PiE this is not visible nor Ai can go here.

Thank you

Hello Vaheva,

I will be glad to look into this for you. Please attach your project files when you reply to this message so that we can reproduce what you are seeing.


Hello Tyler

I have a lot of test stuff in project, I hope map fbx can help. This is just simple fps map with few changes (like a navigation).

Sorry, it can’t be imported this way :stuck_out_tongue: I’m preparing empty project with this nav now, I will post update.

Dropbox link here

I tried it again, and here random results in editor - something low area is marked as “walkable” (blue), sometimes not. In PiE or Simulate never. Maybe I’m doing something wrong, but here a lot of settings… :slight_smile:

If this is not enough, I will try to clean project from not need stuff and send whole (is over 1gb, I have low upload), but on this map I hope navigation should be as expected. This is fps template with starter content, no additional assets.

Than you a lot, I need low area very much :smiley:

Hi again, here goes correct project version:

This is view from editor - is correct - blue area is low as expected and navmodifier is deep blue - same, is ok

here simulate view (same with PIE) with Show Navigation console command:

here NavModifier works, but not works under low area. Low area not working - no blue place.

I did simple settings in project and on map, but this is enough to show my problem I hope.

Hello Vaheva,

Thanks for sending me that project.

I opened the project and I cannot see the low area as blue even when I am in the editor:

Have you made any modifications to the engine itself or your engine settings?



I add two agents to NavMesh in engine settings, but any change in engine itself of course - I’m working here with blueprints only on normal version. And this change is for sure visible in settings - it was saved with this shared project.

Most important - I open this project now to check and I have result same as you - no Blue area even in editor.

I check all settings - they are exactly same as yesterday.

As I post before, this is sometimes very random effect - sometimes I have it in editor not visible too - but I never had it visible in PIE nor simulate. Sometimes when I finally have it in editor, when project is reopened it is lost - like today on your and my side.

Sometime it shows (in editor, never in PIE) after geometry rebuild or other actions, but I really can’t catch when - very random.

Maybe we can try opposing way - if you can set up this or other empty project with NavMesh for normal and LowHeight are and this NavModifierVolume - I will be very happy, because this is very important for my project.

As I understand, low area should be created (this blue) automatically under flow with not sufficient height, but when this height is enough for low area for example. And NavModifier can change normal area to Low (or other selected).

I have also some problems with NavLinks and SmartLinks inside (reandom results on good nav) but this is for other thread I think.

And here my other connected report

I work with ai and navigation months ago, I had break now for coding other parts, but I not work with lowHeight area and many navigation mesh agents, so hard to say it was like this is worked before.

Thank you for your help Tyler :slight_smile:

Hello again - ignore last comment or read as second please.

**Stupid me :stuck_out_tongue_winking_eye: - World Outliner / RecastNavMesh-LowHeight / Display - Enable Drawing must be checked. I had it checked before save and send to you - no idea why is uncheck now!?

Anyway, it have no influence for displaying in PIE, just work in editor - blue area.**

Would be best if it will be displayed in PIE (Show Navigation), but main problem is, AI can’t use it (LowHeigh area etc).

Hello Vaheva,

Ok, I am finally able to reproduce what you are seeing!

NavArea_LowHeight is not typically meant to allow paths through it, as it is generated in spaces without enough height for a character to pass through. Are your AI controlled characters scaled smaller than the Epic Skeleton? Or are you having them crouch to go through it?


Thanks’ God :slight_smile:

Yes, my AI crouching. Now they are crouching without issues when in trigger. I’m using NavLinks and trigger and they walking trough generally good, however some unknown bugs can come (I’m using debuger). Main problem with this solution is, I have to create trigger and NavLink for Crouch always. Next problem, they can walk but without pathfinding, because area is out of NavMesh of course. It creating additional problem and bugs.

So, with Low area working, best would be to send info to AI - they are on Low area and need crouch. I have no idea this is exposed in blueprint, maybe, but rather not - I not found.

But even with trigger in low area (what would be best to avoid), if here will be low area this still is NavMesh (blue) and they can work (AI). Now for example, when they between NavLink points, and they stop for some reason (Behavior Tree) they can stuck. It need a lot of code to avoid and make creating even small levels much harder, not mention open world.

I have “some” experiences with NavMeshes from other engine, but I love UE :slight_smile:

Hello Tyler

Any news? I need lowheight area working very and this is my game part I have now on table.

Hello Vaheva,

I am still working on this and trying to find a solution for you. I don’t have an update at this time, but I will let you know as soon as I have any further information.


Thank you, I will work on other ai - NavMesh parts now. My character can crouch and use low areas, so enemies should too :slight_smile:

Monthly bump - any updates?

@Tyler X Monthly bump - I really should close this game stage.

Hey Vaheva,

Recast Navmesh is only used for optimization of the NavMesh. When in PIE it will not show the Recast even if it is a different color. Using the command ‘Show Navigation’ or using the AI Debugger will also only show the normal Navmesh, not the Low Height area.

Ok, but how to make ai walk crouched in areas like this? Means low?