diff --git a/editor/src/ui.rs b/editor/src/ui.rs
index 30c73ba70f..a1f6bff180 100644
--- a/editor/src/ui.rs
+++ b/editor/src/ui.rs
@@ -92,6 +92,7 @@ impl UI {
         kml: Option<String>,
         window_size: Size,
     ) -> UI {
+        flame::start("setup");
         let (map, edits, control_map, sim) = sim::load(
             load,
             scenario_name,
@@ -109,6 +110,7 @@ impl UI {
         let (draw_map, center_pt) = render::DrawMap::new(&map, &control_map, extra_shapes);
         flame::end("draw_map");
 
+        flame::end("setup");
         flame::dump_stdout();
 
         let steepness_viz = SteepnessVisualizer::new(&map);
diff --git a/geom/src/pt.rs b/geom/src/pt.rs
index d0f07f230b..44104fc781 100644
--- a/geom/src/pt.rs
+++ b/geom/src/pt.rs
@@ -85,6 +85,12 @@ impl fmt::Display for Pt2D {
     }
 }
 
+impl From<HashablePt2D> for Pt2D {
+    fn from(pt: HashablePt2D) -> Self {
+        Pt2D::new(pt.x(), pt.y())
+    }
+}
+
 // This isn't opinionated about what the (x, y) represents -- could be lat/lon or world space.
 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq, PartialOrd, Ord)]
 pub struct HashablePt2D {
diff --git a/map_model/src/make/buildings.rs b/map_model/src/make/buildings.rs
index 12192b4711..e37f901dc6 100644
--- a/map_model/src/make/buildings.rs
+++ b/map_model/src/make/buildings.rs
@@ -5,25 +5,48 @@ use raw_data;
 use std::collections::HashSet;
 use {Building, BuildingID, FrontPath, Lane};
 
-pub(crate) fn make_building(
-    b: &raw_data::Building,
-    id: BuildingID,
+pub(crate) fn make_all_buildings(
+    results: &mut Vec<Building>,
+    input: &Vec<raw_data::Building>,
     bounds: &Bounds,
     lanes: &Vec<Lane>,
-) -> Building {
-    // TODO consume data, so we dont have to clone tags?
-    let points = b.points
-        .iter()
-        .map(|coord| Pt2D::from_gps(coord, bounds))
-        .collect();
-    let front_path = find_front_path(id, &points, lanes);
+) {
+    let mut pts_per_bldg: Vec<Vec<Pt2D>> = Vec::new();
+    let mut center_per_bldg: Vec<HashablePt2D> = Vec::new();
+    let mut query: HashSet<HashablePt2D> = HashSet::new();
+    for b in input {
+        let pts = b.points
+            .iter()
+            .map(|coord| Pt2D::from_gps(coord, bounds))
+            .collect();
+        let center: HashablePt2D = geometry::center(&pts).into();
+        pts_per_bldg.push(pts);
+        center_per_bldg.push(center);
+        query.insert(center);
+    }
 
-    Building {
-        points,
-        front_path,
-        id,
-        osm_way_id: b.osm_way_id,
-        osm_tags: b.osm_tags.clone(),
+    let sidewalk_pts = find_sidewalk_points(query, lanes);
+
+    for (idx, points) in pts_per_bldg.into_iter().enumerate() {
+        let id = BuildingID(idx);
+
+        let bldg_center = center_per_bldg[idx];
+        let (sidewalk, dist_along) = sidewalk_pts[&bldg_center];
+        let (sidewalk_pt, _) = lanes[sidewalk.0].dist_along(dist_along);
+        let line = trim_front_path(&points, Line::new(bldg_center.into(), sidewalk_pt));
+
+        results.push(Building {
+            id,
+            points,
+            osm_tags: input[idx].osm_tags.clone(),
+            osm_way_id: input[idx].osm_way_id,
+            front_path: FrontPath {
+                bldg: id,
+                sidewalk: sidewalk,
+                line,
+                dist_along_sidewalk: dist_along,
+            },
+        });
     }
 }
 
@@ -37,20 +60,3 @@ fn trim_front_path(bldg_points: &Vec<Pt2D>, path: Line) -> Line {
         path
     }
 }
-
-fn find_front_path(bldg: BuildingID, bldg_points: &Vec<Pt2D>, lanes: &Vec<Lane>) -> FrontPath {
-    let bldg_center = geometry::center(bldg_points);
-    let mut query: HashSet<HashablePt2D> = HashSet::new();
-    query.insert(bldg_center.into());
-    let sidewalk_pts = find_sidewalk_points(query, lanes);
-    let (sidewalk, dist_along) = sidewalk_pts.values().next().unwrap();
-    let (sidewalk_pt, _) = lanes[sidewalk.0].dist_along(*dist_along);
-    let line = trim_front_path(bldg_points, Line::new(bldg_center, sidewalk_pt));
-
-    FrontPath {
-        bldg,
-        sidewalk: *sidewalk,
-        line,
-        dist_along_sidewalk: *dist_along,
-    }
-}
diff --git a/map_model/src/make/mod.rs b/map_model/src/make/mod.rs
index 80033b2c19..60027f5754 100644
--- a/map_model/src/make/mod.rs
+++ b/map_model/src/make/mod.rs
@@ -5,7 +5,7 @@ mod sidewalk_finder;
 mod trim_lines;
 mod turns;
 
-pub(crate) use self::buildings::make_building;
+pub(crate) use self::buildings::make_all_buildings;
 pub(crate) use self::bus_stops::make_bus_stops;
 pub(crate) use self::lanes::get_lane_specs;
 pub(crate) use self::trim_lines::trim_lines;
diff --git a/map_model/src/map.rs b/map_model/src/map.rs
index 8a8dc0abbe..3052954fe5 100644
--- a/map_model/src/map.rs
+++ b/map_model/src/map.rs
@@ -172,11 +172,9 @@ impl Map {
 
         {
             let _guard = flame::start_guard(format!("make {} buildings", data.buildings.len()));
-            for (idx, b) in data.buildings.iter().enumerate() {
-                let id = BuildingID(idx);
-                let bldg = make::make_building(b, id, &bounds, &m.lanes);
-                m.lanes[bldg.front_path.sidewalk.0].building_paths.push(id);
-                m.buildings.push(bldg);
+            make::make_all_buildings(&mut m.buildings, &data.buildings, &bounds, &m.lanes);
+            for b in &m.buildings {
+                m.lanes[b.front_path.sidewalk.0].building_paths.push(b.id);
             }
         }