So I have been working with Unity for a while and have long been unable to figure out a solution to this problem. We have are trying to use the Unity Navigation system but even when an solid object is set to not be walkable it will only cut the nav at the shell of the mesh, resulting in islands hidden inside the objects. This is true even using the basic 3d objects built into Unity. Is there any way to avoid this? I would like to avoid having to switch to a new navigation system just because of this one issue but it is a major deal-breaker.