ENH: adding rocket radius to RailButtons class (#643)

* ENH: Enabling the creation of Rail Buttons separately (adding the rocket_radius attribute to the RailButtons class). Improvement of the Railbuttons class.

* ENH: removing unnecessary try except

* ENH: improve try/except block

* DEV: adds 643 to changelog

* ENH: improves add_surfaces for rail buttons

---------

Co-authored-by: Gui-FernandesBR <guilherme_fernandes@usp.br>

Author: juliomachad0

CHANGELOG.md

@@ -35,8 +35,8 @@ Attention: The newest changes should be on top -->
 - 
 
 ### Changed
-
-- 
+ 
+- ENH: Adding rocket radius to RailButtons class [#643](https://github.com/RocketPy-Team/RocketPy/pull/643)
 
 ### Fixed
 
@@ -50,10 +50,10 @@ You can install this version by running `pip install rocketpy==1.4.1`
 
 - Bumps rocketpy version to 1.4.1 [#646](https://github.com/RocketPy-Team/RocketPy/pull/646)
 - ENH: Insert apogee state into solution list during flight simulation [#638](https://github.com/RocketPy-Team/RocketPy/pull/638)
+- MNT: Refactor AeroSurfaces [#634](https://github.com/RocketPy-Team/RocketPy/pull/634)
 - ENH: Environment class major refactor may 2024 [#605](https://github.com/RocketPy-Team/RocketPy/pull/605)
 - MNT: Refactors the code to adopt flake8 [#631](https://github.com/RocketPy-Team/RocketPy/pull/631)
 - MNT: Refactors the code to adopt pylint [#621](https://github.com/RocketPy-Team/RocketPy/pull/621)
-- MNT: Refactor AeroSurfaces [#634](https://github.com/RocketPy-Team/RocketPy/pull/634)
 
 ## [1.4.0] - 2024-07-06
 

rocketpy/rocket/aero_surface/rail_buttons.py

@@ -17,7 +17,13 @@ class RailButtons(AeroSurface):
         relative to one of the other principal axis.
     """
 
-    def __init__(self, buttons_distance, angular_position=45, name="Rail Buttons"):
+    def __init__(
+        self,
+        buttons_distance,
+        angular_position=45,
+        name="Rail Buttons",
+        rocket_radius=None,
+    ):
         """Initializes RailButtons Class.
 
         Parameters
@@ -30,6 +36,10 @@ def __init__(self, buttons_distance, angular_position=45, name="Rail Buttons"):
             relative to one of the other principal axis.
         name : string, optional
             Name of the rail buttons. Default is "Rail Buttons".
+        rocket_radius : int, float, optional
+            Radius of the rocket at the location of the rail buttons in meters.
+            If not provided, it will be calculated when the RailButtons object
+            is added to a Rocket object.
 
         Returns
         -------
@@ -40,7 +50,7 @@ def __init__(self, buttons_distance, angular_position=45, name="Rail Buttons"):
         self.buttons_distance = buttons_distance
         self.angular_position = angular_position
         self.name = name
-
+        self.rocket_radius = rocket_radius
         self.evaluate_lift_coefficient()
         self.evaluate_center_of_pressure()
 

rocketpy/rocket/rocket.py

@@ -947,6 +947,7 @@ def add_surfaces(self, surfaces, positions):
             the root chord which is highest in the rocket coordinate system.
             For Tail type, position is relative to the point belonging to the
             tail which is highest in the rocket coordinate system.
+            For RailButtons type, position is relative to the lower rail button.
 
         See Also
         --------
@@ -956,11 +957,16 @@ def add_surfaces(self, surfaces, positions):
         -------
         None
         """
-        try:
-            for surface, position in zip(surfaces, positions):
+        if not isinstance(surfaces, list):
+            surfaces = [surfaces]
+            positions = [positions]
+
+        for surface, position in zip(surfaces, positions):
+            if isinstance(surface, RailButtons):
+                surface.rocket_radius = surface.rocket_radius or self.radius
+                self.rail_buttons.add(surface, position)
+            else:
                 self.aerodynamic_surfaces.add(surface, position)
-        except TypeError:
-            self.aerodynamic_surfaces.add(surfaces, positions)
 
         self.evaluate_center_of_pressure()
         self.evaluate_stability_margin()
@@ -1512,6 +1518,7 @@ def set_rail_buttons(
         rail_buttons = RailButtons(
             buttons_distance=buttons_distance, angular_position=angular_position
         )
+        rail_buttons.rocket_radius = rail_buttons.rocket_radius or self.radius
         self.rail_buttons.add(rail_buttons, lower_button_position)
         return rail_buttons
 

tests/unit/test_rocket.py

@@ -392,6 +392,15 @@ def test_set_rail_button(calisto):
     ].position == pytest.approx(0.2, 1e-12)
 
 
+def test_add_rail_button(calisto, calisto_rail_buttons):
+    calisto.add_surfaces(calisto_rail_buttons, -0.5)
+    assert calisto.rail_buttons[0].position == -0.5
+    upper_position = (
+        calisto_rail_buttons.buttons_distance + calisto.rail_buttons[0].position
+    )
+    assert upper_position == pytest.approx(0.2, 1e-12)
+
+
 def test_evaluate_total_mass(calisto_motorless):
     """Tests the evaluate_total_mass method of the Rocket class.
     Both with respect to return instances and expected behaviour.