Create a new project using the Blueprint Third Person template (probably doesn’t matter which one).
Add a NavMeshBoundsVolume at 0,0,0 in the level and set its Brush size to cover the level (I used 5000 for x,y,z).
Import a static mesh (anything will do), however, UNTICK the Auto Generate Collision setting on the importer.
Save and close the editor, then reopen the project.
Open your imported static mesh and add collision to it (I added a collision box to mine) and save.
Drag your mesh from the content browser into the level. Notice that the navmesh does NOT update. Try rebuilding your level… still doesn’t update. Doesn’t matter what I try it won’t update. This is the bug.
Save your level and close the editor.
Reopen your project and notice that the navmesh has now updated to account for your mesh (you might have to click rebuild as it doesn’t always seem to account for it straight away until you click rebuild).
If you try importing another static mesh and this time TICK Auto Generate Collisions, then it works fine. So the bug seems to be that manually adding collision to a static mesh requires the editor to be restarted before the navmesh will recognise the collision geometry.
I have been able to reproduce the issue of the NavMesh not updating unless you restart the editor, and have entered a bug report, UE-23125. Thank you for your report.
This issue is currently being investigated by our developers; however, there is currently no timeline for when a fix will be released. I will provide updates on this issue as they become available.
A fix for that would be much appreciated now.
It took me 2 days to understand why my navmesh was not working, before I understand I have to restart unreal to make it work.
I am also running into this issue. Been adjusting settings and exports all day only to find out it appears to be a bug that is almost two years old since reported. Any update?