If a settler can't reach an object (a building, item or resource), that object is marked as unattainable: an icon and a notification are shown.
Settlers no longer try to reach objects marked as unreachable.
Settlers stuck in an enclosed area are marked with an icon and get a separate notification.
Reworked how items drop to the ground: items are now less likely to land in unreachable areas.
Hunters now ignore unreachable animals, both alive and dead.
Hunters now go after the target closest to their hut.
And other pathfinding improvements…
Experimental branch update [0.10.2.b1]
Source: Steam Community (opens in a new tab)