Nav mesh not getting slope angle on imported asset


I am new to UE, I am looking to create a nav mesh on an custom shape geometry made in 3dMax. My first attempt was to import an fbx and apply the navmesh, however the nav generate on a flat horizontal (see plane left). My second attempt was then to convert the fbx to static mesh but the result remain the same. I tried abc, and Datasmith both are not working neither.

I did a test with creating a plane from inside UE, and I do get the slope angle desired, but I can see myself making a bunch of plane to generate the nav mesh desired

Found a temporary fix, it does help to get slope or angle of custom meshes

  1. go to Modeling mode
  2. use the convert mesh
  3. Delete or recast your nav