diff --git a/src/c3nav/routing/graph/room.py b/src/c3nav/routing/graph/room.py
index 9b94e58a..edfcc950 100644
--- a/src/c3nav/routing/graph/room.py
+++ b/src/c3nav/routing/graph/room.py
@@ -38,10 +38,11 @@ class GraphRoom():
                 self._add_ring(interior, want_left=True)
 
         # now fill in missing doorways or similar
-        missing_geometry = self.clear_geometry.difference(geometry.buffer(0.61, join_style=JOIN_STYLE.mitre))
+        accessible_clear_geometry = geometry.buffer(0.31, join_style=JOIN_STYLE.mitre)
+        missing_geometry = self.clear_geometry.difference(accessible_clear_geometry)
         polygons = assert_multipolygon(missing_geometry)
         for polygon in polygons:
-            overlaps = polygon.buffer(0.62).intersection(geometry)
+            overlaps = polygon.buffer(0.02).intersection(accessible_clear_geometry)
             if overlaps.is_empty:
                 continue
 
diff --git a/src/c3nav/routing/utils/coords.py b/src/c3nav/routing/utils/coords.py
index 67e9ecbb..6fc31ced 100644
--- a/src/c3nav/routing/utils/coords.py
+++ b/src/c3nav/routing/utils/coords.py
@@ -33,6 +33,8 @@ def get_coords_angles(geom):
     :rtype: a list of ((x, y), is_left) tuples
     """
     coords = list(cleanup_coords(geom.coords))
+    if len(coords) < 3:
+        return []
     last_coords = coords[-2:]
     last_angle = coord_angle(last_coords[-2], last_coords[-1])
     result = []