MNT: address copilot review

Author: MateusStano

rocketpy/rocket/aero_surface/fins/fin.py

@@ -399,15 +399,20 @@ def _compute_leading_edge_position(self, position, _csys):
         # Rotate the point to the user-defined coordinate system
         p = Vector([p.x * _csys, p.y, p.z * _csys])
 
-        # Calculate the position of the fin leading edge in the user frame
-        # as if no cant angle was applied
-        position = Vector(
-            [
-                -self.rocket_radius * math.sin(self.angular_position_rad) * _csys,
-                self.rocket_radius * math.cos(self.angular_position_rad),
-                position,
-            ]
-        )
+        # Build the leading-edge position in the user frame as if no cant
+        # angle was applied. Scalars are interpreted as z coordinates only,
+        # while vectors/tuples/lists are interpreted as full (x, y, z)
+        # coordinates.
+        if isinstance(position, (Vector, tuple, list)):
+            position = Vector(position)
+        else:
+            position = Vector(
+                [
+                    -self.rocket_radius * math.sin(self.angular_position_rad) * _csys,
+                    self.rocket_radius * math.cos(self.angular_position_rad),
+                    position,
+                ]
+            )
 
         # Translate the position of the fin leading edge to the position of the
         # fin leading edge with cant angle

rocketpy/rocket/aero_surface/fins/trapezoidal_fin.py

@@ -230,6 +230,7 @@ def from_dict(cls, data):
             span=data["span"],
             rocket_radius=data["rocket_radius"],
             cant_angle=data["cant_angle"],
+            sweep_length=data.get("sweep_length"),
             airfoil=data["airfoil"],
             name=data["name"],
         )

rocketpy/rocket/rocket.py

@@ -1365,9 +1365,9 @@ def add_trapezoidal_fins(
         """
         if n <= 2:
             raise ValueError(
-                "Number of fins must be greater than 2."
-                "If you want to add 2 or 1 fins, create a TrapezoidalFin object "
-                " and add it to the rocket using the add_surfaces method."
+                "Number of fins must be greater than 2. "
+                "For 1 or 2 fins, create a FreeFormFin object "
+                "and add it to the rocket using the add_surfaces method."
             )
 
         # Modify radius if not given, use rocket radius, otherwise use given.
@@ -1457,9 +1457,9 @@ def add_elliptical_fins(
         """
         if n <= 2:
             raise ValueError(
-                "Number of fins must be greater than 2."
-                "If you want to add 2 or 1 fins, create a EllipticalFin object "
-                " and add it to the rocket using the add_surfaces method."
+                "Number of fins must be greater than 2. "
+                "For 1 or 2 fins, create a FreeFormFin object "
+                "and add it to the rocket using the add_surfaces method."
             )
 
         radius = radius if radius is not None else self.radius
@@ -1530,9 +1530,9 @@ def add_free_form_fins(
         """
         if n <= 2:
             raise ValueError(
-                "Number of fins must be greater than 2."
-                "If you want to add 2 or 1 fins, create a FreeFormFin object "
-                " and add it to the rocket using the add_surfaces method."
+                "Number of fins must be greater than 2. "
+                "For 1 or 2 fins, create a FreeFormFin object "
+                "and add it to the rocket using the add_surfaces method."
             )
 
         # Modify radius if not given, use rocket radius, otherwise use given.

tests/unit/rocket/aero_surface/test_individual_fins.py

@@ -12,6 +12,7 @@
     TrapezoidalFin,
     TrapezoidalFins,
 )
+from rocketpy.mathutils.vector_matrix import Vector
 
 
 @pytest.mark.parametrize(
@@ -219,6 +220,28 @@ def test_individual_fin_from_dict_roundtrip(
         assert reconstructed.shape_points == fin.shape_points
 
 
+def test_trapezoidal_fin_from_dict_roundtrip_preserves_sweep_length():
+    """Ensure TrapezoidalFin round-trip preserves non-default sweep geometry."""
+    # Arrange
+    original = TrapezoidalFin(
+        angular_position=0,
+        root_chord=0.12,
+        tip_chord=0.04,
+        span=0.1,
+        rocket_radius=0.0635,
+        cant_angle=0,
+        sweep_angle=15.0,
+        name="roundtrip_trapezoidal_fin",
+    )
+    data = original.to_dict()
+
+    # Act
+    reconstructed = TrapezoidalFin.from_dict(data)
+
+    # Assert
+    assert reconstructed.sweep_length == pytest.approx(original.sweep_length)
+
+
 def test_calisto_finset_vs_four_individual_fins_close():
     """Ensure a 4-fin set and 4 individual fins produce close aerodynamics.
 
@@ -294,3 +317,40 @@ def test_calisto_finset_vs_four_individual_fins_close():
     # Assert
     np.testing.assert_allclose(cp_individual, cp_finset, rtol=1e-6, atol=1e-6)
     np.testing.assert_allclose(clalpha_individual_corrected, clalpha_finset)
+
+
+@pytest.mark.parametrize(
+    "position_input",
+    [
+        (0.02, -0.01, -1.2),
+        Vector([0.02, -0.01, -1.2]),
+    ],
+)
+def test_add_individual_fin_accepts_full_3d_position(position_input):
+    """Ensure individual fins accept full (x, y, z) position inputs."""
+    # Arrange
+    rocket = Rocket(
+        radius=0.0635,
+        mass=14.426,
+        inertia=(6.321, 6.321, 0.034),
+        power_off_drag="data/rockets/calisto/powerOffDragCurve.csv",
+        power_on_drag="data/rockets/calisto/powerOnDragCurve.csv",
+        center_of_mass_without_motor=0,
+        coordinate_system_orientation="tail_to_nose",
+    )
+    fin = TrapezoidalFin(
+        angular_position=30,
+        root_chord=0.120,
+        tip_chord=0.040,
+        span=0.100,
+        rocket_radius=0.0635,
+        cant_angle=0,
+        name="position_test_fin",
+    )
+
+    # Act
+    rocket.add_surfaces(fin, position_input)
+    stored_position = rocket.aerodynamic_surfaces[0].position
+
+    # Assert
+    assert stored_position == Vector([0.02, -0.01, -1.2])