NavMesh only works on BSP brushes?

I’m trying to construct a simple level to test out the top down template. However, I the NavMesh seems to be generating only on BSPs.

Things I’ve done so far:

  • Increased the size of the NavMeshBoundsVolume to 10,000uu x 10,000uu.
  • Added basic cube collision meshes (UBX_Mesh) to the FBX models I’ve imported. The player pawn does seem to stand just fine on the meshes.
  • Fiddled with the height of my meshes and the BSP brushes. It seems like the RecastNavMesh is clamped to some specific height value near z = 0, but I’m not sure how to change this.
  • Made a 2000uu x 2000uu x 200uu FBX cube with the same size collision mesh and snapped it next to a BSP brush. No luck.

Here’s an illustration of my problem:

Any help is appreciated, thanks.

NavMesh tests with a new map:

Increasing the “Agent Max Step Height” variable from my RecastNavMesh from 35uu to 90.01uu allowed the NavMesh to expand over the small 400x400x100 platform pieces:

Increasing the “Agent Max Step Height” to 190.01uu allowed the NavMesh to expand over the large 2000x2000x200 platform piece:

So my theory is that the height (Z value) of the StaticMesh must be less than the “Agent Max Step Height” for the NavMesh generator to accept the StaticMesh as part of the NavMesh.

To test this out, I created just a 400uu x 400uu x 0uu plane with a UBX collision mesh of the same size. This doesn’t seem to work:

Toggling the collision mesh inside of UE4 for my plane showed nothing, so I’m thinking collision meshes have to have a non-zero height. Trying again with a new collision mesh (400uu x 400uu x 10uu). The height of the collision mesh (10uu) is lower than the default 35uu “Agent Max Step Height”, so this should work:

And it does.