NavMesh Areas
NavNesh Areas can affect NavNesh generation and agent behavior/pathing. 
The NavMeshArea component is used to define the location, shape and type of an area.
NavNesh Areas can affect NavNesh generation and agent behavior/pathing.
The NavMeshArea component is used to define the location, shape and type of an area.
You can also specify the Area for a link component.
The NavMeshAreaDefinition resource is used to define properties of the Area.
Limitations
- Currently there is a limit of 24 NavMeshAreaDefinition, but you can assign them to as many Area Components as you like
- Static areas are basically free.
- Moving areas are a bit more expensive, but you should be able to have at least a couple of dozens of them.
Referenced API
Canonical API pages mentioned in this guide.
Defines a navigation area resource for use in navigation meshes.
Navigation Mesh - allowing AI to navigate a world
An area that influences the NavMesh generation. Areas can be used to block off parts of the NavMesh. Static areas have almost no performance overhead. Moving areas at runtime will have an impact on performance if done excessively.