I just want to ensure I am going about this the right way, since I am still trying to wrap my head around all this. I guess this is more of a design question, but it's alot to do with multi-player / servers.

1. Create a scene in Unity and exporting the geometry to a file. - Done

2. Load the geometry file in my server code. - Done

Things I am about to attempt, this is where I need to know if this is the correct approach?

3. Create a Navigational Mesh from the Geometry? I am about to test out SharpNav (https://github.com/Robmaister/SharpNav)

4. Use the Navigational Mesh and RayCasting for the players and npc's line of sight and walkable area's?

Sorry hplus0603, the Client is created in Unity3D version 5 and I am using the Lidgren Network library to connect to a custom server built in a C# console application. I am trying to find the best approach to extract the geometry from the scenes I create in Unity3D into a file that my server can read. Currently I am exporting the terrain to a .obj file but I may see about just exporting just the triangles since the server doesn't care about textures.

I want the server to do all the raycasting (line of sight) for spell casting and ranged combat, also have the server calculate the walkable areas for players / npc's via a navigational mesh (SharpNav).

Has anyone used SharpNav? Are there any other navmesh libraries in C#?

The setup I am aiming for for raycasting / walkable areas using the geometry file on the server is this the best approach?

I love the way EQEmulator folks have the server implemented, so I would like to model mine in a similar way but in C#. (https://github.com/EQEmu/Server/)

Ahh good point on tagging certain places in the zone, thanks. I think I will explore this path for the server.