I've done some reading on nav-meshes, and I understand how to generate a path of polygons to reach a goal. However, what I don't understand is how you determine the bearing to follow within each polygon. Without a central node to aim for, what do you aim for?

![Navigation mesh example from UDN][1]


  [1]: https://i.sstatic.net/nCEQ4.gif

http://udn.epicgames.com/Three/NavigationMeshReference.html