6DoF navmeshes or navmeshes on ceilngs/walls possible?

As a new developer with little to no experience in C (I have used other scripting languages for mod related projects for other games), I am looking into developing a 6DoF shooter sometime in the future.

Some good examples of this type of game are: The Descent series, Forsaken, Overload.

Levels would be constructed as massive underground mazes.

I was wondering if Unity navmeshes support AI such as the enemy robots found in the above listed games?

If not, I was thinking that I could go a more unique route and make the player vehicle a hovercraft, and the levels could use directional gravity to allow the hovercraft and robots to navigate through the levels? That is, if the navmesh system allows me to scale walls and ceilings with it?

 

Overload is made with Unity. They would have made their own pathfinding, since the built-in navmesh isn't really suitable for a 6DOF game, plus they use their own level editor. Unity doesn't use C, but rather C#.

--Eric

 

Sorry, I refer to it as C here because I have been looking at Unreal Engine as well, which uses C++ rather than C#. What about scaling walls/ceilings? As mentioned before, that could be an interesting alternative and could provide a bit of puzzle/problem solving gameplay as well.

I am also aware that Overload is made with Unity, part of the reason I wanted to look into Unity to see if it would be a more practical choice. They also do have their own level editor, as it is a cube based system, but is pretty limited in what can be made with it. I would be going a different route in terms of level design.