# Navmesh generating under ground ?!

**URL:** <https://forums.unrealengine.com/t/navmesh-generating-under-ground/483307>\
**Category:** World Creation\
**Tags:** Navigation, dynamic-navmesh, navmeshbounds, navmesh-bug, unreal-engine, navmesh, question\
**Created:** [May 13, 2021, 4:13am UTC](https://forums.unrealengine.com/t/navmesh-generating-under-ground/483307 "2021-05-13T04:13:57Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Jau\_Studio](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/jau_studio/32/886547_2.png) [@Jau\_Studio](https://forums.unrealengine.com/u/Jau_Studio)\
**Post date:** [May 13, 2021, 4:13am UTC](https://forums.unrealengine.com/t/navmesh-generating-under-ground/483307/1 "2021-05-13T04:13:57Z")

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Hello,

I’m working on an open world with World Composition. I’m using a dynamic Navmesh and invokers to generate it.

As you can see on the screenshot, on this big hill, the Navmesh is generated _under_ the ground.  
Not at the rest of the ground level (outside of the hill) but almost at half-distance.

If I add an NPC directly on the landscape (not on a “slab” mesh), the result is the same. As if there was some kind of “max height” to the Navmesh…

Any Idea why ?

 ![338674-navmesh-wrong-underground.jpg](https://d3kjluh73b9h9o.cloudfront.net/original/4X/b/5/4/b5430ac533c9f2133db05edea8c3250c4c32a121.jpeg)

Thank you so much !

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**Author:** ![mindsurferdev](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@mindsurferdev](https://forums.unrealengine.com/u/mindsurferdev)\
**Post date:** [May 13, 2021, 4:18am UTC](https://forums.unrealengine.com/t/navmesh-generating-under-ground/483307/2 "2021-05-13T04:18:59Z")

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Could it be that the ground mesh is bigger/smaller than the collision of the ground?

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<div class="post-metadata">

**Author:** ![Jau\_Studio](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/jau_studio/32/886547_2.png) [@Jau\_Studio](https://forums.unrealengine.com/u/Jau_Studio)\
**Post date:** [May 13, 2021, 8:59am UTC](https://forums.unrealengine.com/t/navmesh-generating-under-ground/483307/3 "2021-05-13T08:59:22Z")

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No the meshes have basic box collisions.  
I just found a weird solution here : [https://answers.unrealengine.com/questions/965471/view.html](https://answers.unrealengine.com/questions/965471/view.html)  
Increase the Cell Height.  
I set it at 250 lol. I guess the “cubes” building the Navmesh were not big enough to reach ?

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**Author:** ![Cykablatta](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Cykablatta](https://forums.unrealengine.com/u/Cykablatta)\
**Post date:** [July 1, 2025, 7:13am UTC](https://forums.unrealengine.com/t/navmesh-generating-under-ground/483307/4 "2025-07-01T07:13:05Z")

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Did you try setting “Fill Collision Underneath for NavMesh” (NavMeshBounds Volume details) as false?