diff --git a/docs/how-to/guide_rad1.md b/docs/how-to/guide_rad1.md
index 4c840e7..affea25 100644
--- a/docs/how-to/guide_rad1.md
+++ b/docs/how-to/guide_rad1.md
@@ -143,7 +143,7 @@ The code block demonstrates how we generate a grid of sensors with
 1 meter spacing and 0.75 meters away from the floor:
 
 ```py
-floor_primitives = fr.unpack_primitive("Objects/floor_aroom.rad")
+floor_primitives = fr.unpack_primitives("Objects/floor_aroom.rad")
 # Since we only have one primitive in this file,
 # we'll take the first one to parse.
 floor_polygon = fr.parse_polygon(floor_primitives[0])
diff --git a/frads/methods.py b/frads/methods.py
index bf6df4d..3677246 100755
--- a/frads/methods.py
+++ b/frads/methods.py
@@ -102,8 +102,7 @@ class ShadingGeometryConfig:
     shading_geometry_file: Union[str, Path] = ""
     shading_geometry_bytes: Optional[np.ndarray] = None
 
-    def __post_init__(self):
-        ...
+    def __post_init__(self): ...
 
 
 @dataclass
@@ -502,6 +501,7 @@ def __post_init__(self):
                         f"{k} matrix name {v.matrix_name} not found in materials"
                     )
 
+
 @dataclass
 class WorkflowConfig:
     """Workflow configuration dataclass.
@@ -598,13 +598,8 @@ def __init__(self, config: WorkflowConfig):
                 view.view, xres=view.xres, yres=view.yres
             )
         for name, surface in self.config.model.surfaces.items():
-            polygons = [parse_polygon(p) for p in surface.primitives]
-            flipped_primitives = [
-                polygon_primitive(p.flip(), s.modifier, s.identifier)
-                for p, s in zip(polygons, surface.primitives)
-            ]
             self.surface_senders[name] = SurfaceSender(
-                surfaces=flipped_primitives,
+                surfaces=surface.primitives,
                 basis=surface.basis,
             )
 
diff --git a/frads/room.py b/frads/room.py
index 0318594..92a3fea 100755
--- a/frads/room.py
+++ b/frads/room.py
@@ -7,6 +7,7 @@
 from frads import utils
 import numpy as np
 
+
 @dataclass
 class WindowSurface:
     polygon: Polygon
@@ -23,7 +24,6 @@ class Surface:
     identifier: str
     primitives: List[pr.Primitive]
 
-
     def move_window(self, distance: float) -> None:
         """Move windows in its normal direction."""
         direction = self.base.normal * distance
@@ -48,7 +48,9 @@ def rotate_z(self, radians):
             modifier=self.base_primitive.modifier,
             identifier=self.base_primitive.identifier,
         )
-        new_polygons = [plg.rotate(center, zaxis, radians) for plg in self.polygons]
+        new_polygons = [
+            plg.rotate(center, zaxis, radians) for plg in self.polygons
+        ]
         new_primitives = []
         for idx, polygon in enumerate(new_polygons):
             new_primitives.append(
@@ -75,8 +77,6 @@ def rotate_z(self, radians):
         self.base_primitive = new_base_primitive
 
 
-
-
 @dataclass
 class Room:
     floor: Surface
@@ -106,11 +106,14 @@ def window_primitives(self) -> List[pr.Primitive]:
             *[srf.primitive for srf in self.wwall.windows],
         ]
 
-
     def model_dump(self) -> dict:
         model = {}
-        model["materials"] = {"bytes": b" ".join(p.bytes for p in self.materials)}
-        model["scene"] = {"bytes": b" ".join(p.bytes for p in self.primitives())}
+        model["materials"] = {
+            "bytes": b" ".join(p.bytes for p in self.materials)
+        }
+        model["scene"] = {
+            "bytes": b" ".join(p.bytes for p in self.primitives())
+        }
         model["windows"] = {}
         for primitive in self.window_primitives():
             model["windows"][primitive.identifier] = {"bytes": primitive.bytes}
@@ -133,7 +136,6 @@ def rotate_z(self, radians):
         self.wwall.rotate_z(radians)
         self.nwall.rotate_z(radians)
 
-
     def validate(self) -> None:
         """Validate the room model."""
         material_names = [p.identifier for p in self.materials]
@@ -163,7 +165,7 @@ def make_window(
     dist_left: float,
     dist_bot: float,
     width: float,
-    height: float
+    height: float,
 ) -> Tuple[Polygon, WindowSurface]:
     """Make one or more window and punch a hole.
 
@@ -199,13 +201,11 @@ def make_window(
             polygon=window_polygon,
             modifier="glass_60",
             identifier=name,
-        )
+        ),
     )
 
-def make_window_wwr(
-    base: Polygon,
-    wwr: float
-) -> Tuple[Polygon, WindowSurface]:
+
+def make_window_wwr(base: Polygon, wwr: float) -> Tuple[Polygon, WindowSurface]:
     """
     Make a single window and punch a hole based on window-to-wall ratio.
 
@@ -218,7 +218,7 @@ def make_window_wwr(
             polygon=window_polygon,
             modifier="glass_60",
             identifier="void",
-        )
+        ),
     )
 
 
@@ -306,13 +306,16 @@ def create_south_facing_room(
 ) -> Room:
     materials = list(utils.material_lib().values())
     pt1 = np.array((0, 0, 0))
-    pt2 = pt1 + np.array((width, 0, 0))
-    pt3 = pt2 + np.array((0, depth, 0))
+    pt2 = pt1 + np.array((0, depth, 0))
+    pt3 = pt2 + np.array((width, 0, 0))
     base_floor = Polygon.rectangle3pts(pt1, pt2, pt3)
-    _, base_ceiling, base_swall, base_ewall, base_nwall, base_wwall = base_floor.extrude(
-        np.array((0, 0, floor_floor))
+    _, base_ceiling, base_wwall, base_nwall, base_ewall, base_swall = (
+        base_floor.extrude(np.array((0, 0, floor_floor)))
+    )
+    base_ceiling = base_ceiling.flip()
+    base_ceiling = base_ceiling.move(
+        np.array((0, 0, floor_ceiling - floor_floor))
     )
-    base_ceiling = base_ceiling.move(np.array((0, 0, floor_ceiling - floor_floor)))
     floor = create_surface(
         base_floor,
         modifier="neutral_lambertian_0.2",