How to bake navmesh on walls?

I want to make this - YouTube , but with pathfinding system. Could RAIN AI help me? Or maybe there is some tricky way to do this. I could even write my own pathfinding system that would work in any angle, only if there isnt another way. It could be more than enough, if I would be able to set navmesh position on floor, walls and celing, like in the video I linked, but only on cube surface (90 degrees only).

It’s now possible

go into 6:38

They are using NavMeshSurface and NavMeshBuilder.
You can also do a lot of neat stuff, such as different navmeshes in the same scene, for different agent types, navMeshObstacles for specific agent types etc

Notice, afaik it’s not a part of the standard package of unity (2017), so you will need to google them and see how to import into your project (similar to the Standard Assets package)