Overview

The Navigation Mode allows you to create/edit the navigation mesh (aka NavMesh or AI map) of a level. This is required for the AI (enemies, friends, etc.) to move around the level. They will always be inside a Navmesh, otherwise, errors may occur.

To access the Navigation Editor, look for Navigation on the Mode Toolbar.

This mode allows only for creating/editing the navmesh, so you won't be able to select meshes, enemies, covers, etc. If you haven't created a navmesh yet, the scene appears in the game mode (CTRL+E), otherwise, you should see your navmesh in the scene.

Tools 

In the Navigation Mode, you have 2 sub-menus: mesh and navigation.

Most of them are self-explanatory, but here is some information about them. For in-editor information, just hover the mouse on top of the tool you want to use.

Icon	Tool	Description	Shortcut
	Select Vertex, Edge, Face	Toggle vertex, edge, and face selection.	V, E, F (respectively)
	Weld Vertex	Combine 2 or more vertices together (similar to merge/merge to center in Maya).	W
	Rotate Edge	Will change the "triangulation" of the edge. This will simply change the vertex that is connected to the edge. Does not work on borders.	R
	Drop Vertex	Will attach the vertex to the nearest surface.	D
	Snap Vertex, Edge, Face, Object	Toggle vertex, edge, and face snapping.	ALT+ V / E / F / O (respectively)
	Top View, Near View	Makes the navmesh overlap on top/near objects. Good for seeing the navmesh on top of everything.	Z, N (respectively)
	Fan	Toggle On/Off for a fan creation. Pay attention to the color of the vertices.	M
	Draw Border	Show/hide borders of a navmesh.	B
	Create Tri	Creates a triangle with the selected vertices.	C
	Tesselate Tris	Face Tessellation Utility – a convenient way to create AI maps for terrains. Set the Edge length (desired triangle's edge length) property in the Tool tab. Select the faces you want tessellated or simplified. Press Tesselate Tris (T) on the top panel (simplification is also there).	T
	Simplify Selected	Simplifies the selected tris.	CTRL+D
	Check Errors	Check for errors in the navmesh. It will automatically select those faces that contain errors. Use Zoom Selected (Shortcut: Home) to zoom in on the selection. Zoom Selected only works, if you have the face selection on. If nothing happens when you click, congratulations! No errors.	CTRL+V
	Unassigned Verts	Selects vertices that are unassigned to a navmesh. Delete them!	CTRL+U
	Select Adj Tris	Select adjacent faces/tris.	CTRL+T
	Select Adj Verts	Select adjacent vertices.	CTRL+P
PE Update		Calculates any changes you've made to the navmesh. It will ask you to re-calculate, if you changed a navmesh and pressed "play".	CTRL+ALT+S
PE Covers		Calculates any changes you've made to covers. It will ask you to re-calculate, if you changed a navmesh and pressed "play".	CTRL+ALT+S

Creating a navmesh

Navmesh is like a 3D model, it has vertices, edges, and faces.

There are 2 ways to create a navmesh:

1. Use the Shortcut: CTRL+RMB to place a vertex. Continue to add two more to create a triangle.
   
2. Use the Shortcut: RMB to place a vertex. Continue to place two more, select the three of them, and use the Shortcut: C to create a triangle.
   
   
   

After that, you should have something like the image below. The green walls represent boundaries of the navmesh, while the red ground represents actual area that the AI can use.

Vertices' colors have meanings:

Adjust it to your scene. Remember, the red area is exactly where the AI/NPC will walk, so if you need more detail, use the tessellation tool (explained below). 

After adjusting to your scene

There is no need to connect every navmesh at the level, or to create it perfectly. NPCs or monsters can use covers to "jump" between navmeshes and have auto-adjustments for the feet height.

Editing the AI-map 

Adding vertices 

1. Toggle the vertex selection mode (shortcut: V).
   
2. Add new vertices to your navmesh (shortcut: Ctrl + RMB). 
   
   
   

Adding the edges 

There are 2 ways to add new edges: 

1. Toggle the edge selection mode (shortcut: E).
2. Add new edges to your navmesh (shortcut: Ctrl + RMB). 
   
   

Or 

1. Toggle the edge selection mode (shortcut: E).
2. Add new edges to your navmesh (shortcut: Ctrl + Alt + RMB). 
   
   

Selecting elements 

You can select elements by clicking the LMB on the element. If you want to select several objects, hold Ctrl while selecting. 

To select many vertices, faces, or edges at once (which depends on what selection mode is active), drag the mouse over the elements while holding the LMB. All items that fall into the selection area will be selected.

Deleting elements 

• If the vertex selection mode is enabled, deleting the vertex (or vertices) will remove all triangles, to which the selected point belongs.
• If the face selection mode is enabled, this deletes only the selected faces.

Multi-Cut Tool

• On the active layer on which the AI map grid is located, hold down the combination Ctrl + Alt + LMB and drag. As you do so, a line will appear. When you release, a new vertex will be created at the intersection of the line and the edges.
• You can also cut from vertex to vertex.

Moving elements 

To move an object, select and move it, holding LMB, to your desired place.

Properties

Common 

Vertex

Face