When adding a Smart Object, make sure its entry and exit points are within the navigation mesh area. An incorrectly placed Smart Object will flash red.
For an AI character to be able to use the Smart Object, its agent type definition should list one or more Smart Object User Classes which the Smart Object has.
For example, if a Smart Object has class Human and an AI character is of agent type MediumSizedCharacters, the following lines should present in the
Scripts/AI/Navigation.xml file, within tag <AgentType name="MediumSizedCharacters" ... >:
The usual debug draw for the Smart Object will show if it is properly connected to the navigation mesh.
Also, you can set ai_DebugDrawNavigation to 3 to display the linked triangles (the ones with red edges).
It is also possible to use AI Paths for off-mesh navigation. This can be useful for intersecting multiple separate MNM areas, if AI need to traverse between them.
Care should be taken when using AI Paths in this manner however. If an AI manages to get into combat during the AI Path travels, they can become stuck as they have no freedom of movement like they would inside an MNM area.
Unless your level markup ensures it, off-mesh navigation should be done as non-interruptible in the AISequence:Start node.