diff --git a/convert_osm/src/clip.rs b/convert_osm/src/clip.rs
index 6aa3974c87..6b50c9dd6c 100644
--- a/convert_osm/src/clip.rs
+++ b/convert_osm/src/clip.rs
@@ -50,7 +50,7 @@ pub fn clip_map(map: &mut raw_data::Map, path: &str, timer: &mut Timer) -> GPSBo
         if map
             .roads
             .values()
-            .filter(|r2| r2.i1 == move_i || r2.i1 == move_i)
+            .filter(|r2| r2.i1 == move_i || r2.i2 == move_i)
             .count()
             > 1
         {
diff --git a/editor/src/objects.rs b/editor/src/objects.rs
index efb242efcd..969c7882e7 100644
--- a/editor/src/objects.rs
+++ b/editor/src/objects.rs
@@ -94,7 +94,7 @@ impl ID {
             ID::Lane(id) => map.maybe_get_l(id).map(|l| l.first_pt()),
             ID::Intersection(id) => map.maybe_get_i(id).map(|i| i.point),
             ID::Turn(id) => map.maybe_get_i(id.parent).map(|i| i.point),
-            ID::Building(id) => map.maybe_get_b(id).map(|b| Pt2D::center(&b.points)),
+            ID::Building(id) => map.maybe_get_b(id).map(|b| b.polygon.center()),
             ID::Car(id) => sim.get_draw_car(id, map).map(|c| c.body.last_pt()),
             ID::Pedestrian(id) => sim.get_draw_ped(id, map).map(|p| p.pos),
             // TODO maybe_get_es
diff --git a/editor/src/render/building.rs b/editor/src/render/building.rs
index 3d6b3e6387..dd948cffcb 100644
--- a/editor/src/render/building.rs
+++ b/editor/src/render/building.rs
@@ -7,6 +7,7 @@ use map_model::{Building, BuildingID, BuildingType, LANE_THICKNESS};
 
 pub struct DrawBuilding {
     pub id: BuildingID,
+    // TODO Stop storing a copy here
     pub fill_polygon: Polygon,
     front_path: Polygon,
 
@@ -26,7 +27,6 @@ impl DrawBuilding {
                 front_path_line.dist_along(len - trim_back),
             );
         }
-        let fill_polygon = Polygon::new(&bldg.points);
         let front_path = front_path_line.make_polygons(Distance::meters(1.0));
 
         let default_draw = prerender.upload_borrowed(vec![
@@ -42,14 +42,14 @@ impl DrawBuilding {
                         cs.get_def("unknown building", Color::rgb_f(0.7, 0.7, 0.7))
                     }
                 },
-                &fill_polygon,
+                &bldg.polygon,
             ),
             (cs.get_def("building path", Color::grey(0.6)), &front_path),
         ]);
 
         DrawBuilding {
             id: bldg.id,
-            fill_polygon,
+            fill_polygon: bldg.polygon.clone(),
             front_path,
             default_draw,
         }
diff --git a/halloween/src/render.rs b/halloween/src/render.rs
index 369982f69d..9e01aec669 100644
--- a/halloween/src/render.rs
+++ b/halloween/src/render.rs
@@ -92,7 +92,7 @@ impl DrawBuilding {
     fn new(b: &Building) -> DrawBuilding {
         DrawBuilding {
             id: b.id,
-            polygon: Polygon::new(&b.points),
+            polygon: b.polygon.clone(),
             line: b.front_path.line.reverse(),
         }
     }
diff --git a/map_model/src/building.rs b/map_model/src/building.rs
index 9d192af0f7..f799240e4d 100644
--- a/map_model/src/building.rs
+++ b/map_model/src/building.rs
@@ -1,6 +1,6 @@
 use crate::{LaneID, Position};
 use abstutil;
-use geom::{Line, Pt2D};
+use geom::{Line, Polygon};
 use serde_derive::{Deserialize, Serialize};
 use std::collections::BTreeMap;
 use std::fmt;
@@ -34,7 +34,7 @@ pub enum BuildingType {
 pub struct Building {
     pub id: BuildingID,
     pub building_type: BuildingType,
-    pub points: Vec<Pt2D>,
+    pub polygon: Polygon,
     pub osm_tags: BTreeMap<String, String>,
     pub osm_way_id: i64,
     pub num_residential_units: Option<usize>,
diff --git a/map_model/src/make/buildings.rs b/map_model/src/make/buildings.rs
index 16e54a5559..d90d9a60ae 100644
--- a/map_model/src/make/buildings.rs
+++ b/map_model/src/make/buildings.rs
@@ -1,7 +1,7 @@
 use crate::make::sidewalk_finder::find_sidewalk_points;
 use crate::{raw_data, Building, BuildingID, BuildingType, FrontPath, Lane};
 use abstutil::Timer;
-use geom::{Bounds, Distance, GPSBounds, HashablePt2D, Line, Pt2D};
+use geom::{Bounds, Distance, GPSBounds, HashablePt2D, Line, Polygon, Pt2D};
 use std::collections::{BTreeMap, HashSet};
 
 pub fn make_all_buildings(
@@ -47,7 +47,7 @@ pub fn make_all_buildings(
             results.push(Building {
                 id,
                 building_type: classify(input[idx].num_residential_units, &input[idx].osm_tags),
-                points,
+                polygon: Polygon::new(&points),
                 osm_tags: input[idx].osm_tags.clone(),
                 osm_way_id: input[idx].osm_way_id,
                 front_path: FrontPath {
diff --git a/map_model/src/neighborhood.rs b/map_model/src/neighborhood.rs
index 98329cf6d9..bd59ba00fe 100644
--- a/map_model/src/neighborhood.rs
+++ b/map_model/src/neighborhood.rs
@@ -83,7 +83,7 @@ impl Neighborhood {
     pub fn find_matching_buildings(&self, map: &Map) -> Vec<BuildingID> {
         let mut results: Vec<BuildingID> = Vec::new();
         for b in map.all_buildings() {
-            if self.polygon.contains_pt(Pt2D::center(&b.points)) {
+            if self.polygon.contains_pt(b.polygon.center()) {
                 results.push(b.id);
             }
         }
diff --git a/tests/src/map_conversion.rs b/tests/src/map_conversion.rs
index b4748ac217..0c96677330 100644
--- a/tests/src/map_conversion.rs
+++ b/tests/src/map_conversion.rs
@@ -14,6 +14,7 @@ pub fn run(t: &mut TestRunner) {
             parking_shapes: "../data/shapes/blockface".to_string(),
             gtfs: "../data/input/google_transit_2018_18_08".to_string(),
             neighborhoods: "../data/input/neighborhoods.geojson".to_string(),
+            clip: "../data/polygons/montlake.poly".to_string(),
             output: "convert_osm_twice".to_string(),
             fast_dev: false,
         };