ENH: new dimensions route to get rocket geometry (#71)

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: aasitvora99

requirements.txt

@@ -9,7 +9,7 @@ pymongo>=4.15
 jsonpickle
 gunicorn
 uvicorn
-git+https://github.com/RocketPy-Team/RocketPy.git@develop
+rocketpy
 uptrace
 opentelemetry.instrumentation.fastapi
 opentelemetry.instrumentation.requests

src/controllers/motor.py

@@ -2,7 +2,7 @@
     ControllerBase,
     controller_exception_handler,
 )
-from src.views.motor import MotorSimulation
+from src.views.motor import MotorSimulation, MotorDrawingGeometryView
 from src.models.motor import MotorModel
 from src.services.motor import MotorService
 
@@ -57,3 +57,27 @@ async def get_motor_simulation(self, motor_id: str) -> MotorSimulation:
         motor = await self.get_motor_by_id(motor_id)
         motor_service = MotorService.from_motor_model(motor.motor)
         return motor_service.get_motor_simulation()
+
+    @controller_exception_handler
+    async def get_motor_drawing_geometry(
+        self, motor_id: str
+    ) -> MotorDrawingGeometryView:
+        """
+        Build the motor-only drawing-geometry payload for a persisted motor.
+
+        Renders the motor at its own coordinate origin (motor_position=0,
+        parent_csys=1) so the playground can show a motor in isolation.
+
+        Args:
+            motor_id: str
+
+        Returns:
+            views.MotorDrawingGeometryView
+
+        Raises:
+            HTTP 404 Not Found: If the motor does not exist in the database.
+            HTTP 422: If the motor has no drawable geometry.
+        """
+        motor = await self.get_motor_by_id(motor_id)
+        motor_service = MotorService.from_motor_model(motor.motor)
+        return motor_service.get_drawing_geometry()

src/controllers/rocket.py

@@ -4,7 +4,11 @@
     ControllerBase,
     controller_exception_handler,
 )
-from src.views.rocket import RocketSimulation, RocketCreated
+from src.views.rocket import (
+    RocketSimulation,
+    RocketCreated,
+    RocketDrawingGeometry,
+)
 from src.models.motor import MotorModel
 from src.models.rocket import (
     RocketModel,
@@ -75,6 +79,27 @@ async def get_rocketpy_rocket_binary(self, rocket_id: str) -> bytes:
         rocket_service = RocketService.from_rocket_model(rocket.rocket)
         return rocket_service.get_rocket_binary()
 
+    @controller_exception_handler
+    async def get_rocket_drawing_geometry(
+        self, rocket_id: str
+    ) -> RocketDrawingGeometry:
+        """
+        Build the drawing geometry payload for a persisted rocket.
+
+        Args:
+            rocket_id: str
+
+        Returns:
+            views.RocketDrawingGeometry
+
+        Raises:
+            HTTP 404 Not Found: If the rocket does not exist in the database.
+            HTTP 422: If the rocket has no aerodynamic surfaces to draw.
+        """
+        rocket = await self.get_rocket_by_id(rocket_id)
+        rocket_service = RocketService.from_rocket_model(rocket.rocket)
+        return rocket_service.get_drawing_geometry()
+
     @controller_exception_handler
     async def get_rocket_simulation(
         self,

src/models/motor.py

@@ -82,6 +82,22 @@ def validate_motor_kind(self):
             )
         return self
 
+    @model_validator(mode='after')
+    def validate_dry_inertia_for_kind(self):
+        # RocketPy's SolidMotor/LiquidMotor/HybridMotor require dry_inertia with no default.
+        # Only GenericMotor accepts (0, 0, 0). Surface a clear error at the API boundary
+        # instead of letting RocketPy crash deep in construction.
+        if self.motor_kind != MotorKinds.GENERIC and self.dry_inertia == (
+            0,
+            0,
+            0,
+        ):
+            raise ValueError(
+                f"dry_inertia is required for {self.motor_kind} motors "
+                f"and must be explicitly provided (cannot be (0, 0, 0))."
+            )
+        return self
+
     @staticmethod
     def UPDATED():
         return

src/models/sub/tanks.py

@@ -22,7 +22,8 @@ class MotorTank(BaseModel):
     liquid: TankFluids
     flux_time: Tuple[float, float]
     position: float
-    discretize: int
+    # discretize is optional in RocketPy's Tank classes (defaults to 100).
+    discretize: int = 100
 
     # Level based tank parameters
     liquid_height: Optional[float] = None

src/routes/motor.py

@@ -9,6 +9,7 @@
     MotorSimulation,
     MotorCreated,
     MotorRetrieved,
+    MotorDrawingGeometryView,
 )
 from src.models.motor import MotorModel
 from src.dependencies import MotorControllerDep
@@ -138,3 +139,24 @@ async def get_motor_simulation(
     """
     with tracer.start_as_current_span("get_motor_simulation"):
         return await controller.get_motor_simulation(motor_id)
+
+
+@router.get("/{motor_id}/drawing-geometry")
+async def get_motor_drawing_geometry(
+    motor_id: str,
+    controller: MotorControllerDep,
+) -> MotorDrawingGeometryView:
+    """
+    Returns motor-only drawing geometry so a frontend can render the
+    motor in isolation. The payload mirrors what the motor portion of
+    `rocketpy.Rocket.draw()` would produce, but at the motor's own
+    coordinate origin rather than embedded inside a rocket.
+
+    Use `GET /rockets/{rocket_id}/drawing-geometry` instead when the
+    motor should be shown inside a complete rocket.
+
+    ## Args
+    ``` motor_id: Motor ID ```
+    """
+    with tracer.start_as_current_span("get_motor_drawing_geometry"):
+        return await controller.get_motor_drawing_geometry(motor_id)

src/routes/rocket.py

@@ -9,6 +9,7 @@
     RocketSimulation,
     RocketCreated,
     RocketRetrieved,
+    RocketDrawingGeometry,
 )
 from src.models.rocket import (
     RocketModel,
@@ -181,3 +182,23 @@ async def simulate_rocket(
     """
     with tracer.start_as_current_span("get_rocket_simulation"):
         return await controller.get_rocket_simulation(rocket_id)
+
+
+@router.get("/{rocket_id}/drawing-geometry")
+async def get_rocket_drawing_geometry(
+    rocket_id: str,
+    controller: RocketControllerDep,
+) -> RocketDrawingGeometry:
+    """
+    Returns structured drawing geometry for the rocket so that a frontend
+    can redraw exactly what rocketpy.Rocket.draw() would render.
+
+    Response contains shape coordinate arrays for each aerodynamic surface,
+    tube segments, motor polygons (nozzle, chamber, grains, tanks, outline),
+    rail-button positions, CG/CP at t=0, sensors, and overall drawing bounds.
+
+    ## Args
+    ``` rocket_id: Rocket ID ```
+    """
+    with tracer.start_as_current_span("get_rocket_drawing_geometry"):
+        return await controller.get_rocket_drawing_geometry(rocket_id)