Hello! I'm currently working on a worldspace mod which needs navmesh. I started using navmesh just the other day and have only learned the basics. everthing works smooth except for one particular staircase.. It looks like this part of the stair is located in the corner of another cell, and I just can't finalize it. every time when I'm done placing the navmesh (so that it looks good) and press Finalize, or even "save" it just deletes itself and all the triangles within. why?

Cell boundaries can be a bit tricky.

Are you making sure any vertices you place on the boundary line from one cell has a matching vert from the adjacent cell that is placed so they are on top of each other? You'll know you got it right as when you finalise, the edge will have a green rectangle along it, signifying a working cross over point

- Hypno