Add motor bracket mechanism and example

parametric_cad/examples/motor_bracket_example.py

@@ -0,0 +1,7 @@
+from parametric_cad.mechanisms.motor_bracket import RightAngleMotorBracket
+from parametric_cad.export.stl import STLExporter
+
+bracket = RightAngleMotorBracket()
+
+exporter = STLExporter(output_dir="output/motor_bracket_output")
+exporter.export_mesh(bracket.mesh(), "motor_bracket")

parametric_cad/mechanisms/motor_bracket.py

@@ -0,0 +1,88 @@
+import numpy as np
+from math import pi
+from parametric_cad.core import tm, safe_difference
+
+class RightAngleMotorBracket:
+    """Simple right angle bracket for a 540/550 size motor."""
+
+    def __init__(
+        self,
+        base_length: float = 50.0,
+        base_width: float = 40.0,
+        plate_height: float = 40.0,
+        thickness: float = 3.0,
+        motor_hole_spacing: float = 25.0,
+        motor_hole_diameter: float = 3.2,
+        shaft_clearance_diameter: float = 10.0,
+        motor_mount_height: float = 20.0,
+    ) -> None:
+        self.base_length = base_length
+        self.base_width = base_width
+        self.plate_height = plate_height
+        self.thickness = thickness
+        self.motor_hole_spacing = motor_hole_spacing
+        self.motor_hole_diameter = motor_hole_diameter
+        self.shaft_clearance_diameter = shaft_clearance_diameter
+        self.motor_mount_height = motor_mount_height
+        self._mesh = self._create_bracket()
+
+    def _create_bracket(self) -> tm.Trimesh:
+        # Base plate
+        base = tm.creation.box(
+            extents=(self.base_length, self.base_width, self.thickness)
+        )
+        base.apply_translation(
+            [self.base_length / 2, self.base_width / 2, self.thickness / 2]
+        )
+
+        # Vertical plate
+        plate = tm.creation.box(
+            extents=(self.base_length, self.thickness, self.plate_height)
+        )
+        plate.apply_translation(
+            [
+                self.base_length / 2,
+                self.base_width - self.thickness / 2,
+                self.thickness + self.plate_height / 2,
+            ]
+        )
+
+        bracket = tm.util.concatenate([base, plate])
+
+        # Create mounting holes
+        holes = []
+        hole_y = self.base_width - self.thickness / 2
+        hole_z = self.thickness + self.motor_mount_height
+        for x_off in [
+            self.base_length / 2 - self.motor_hole_spacing / 2,
+            self.base_length / 2 + self.motor_hole_spacing / 2,
+        ]:
+            cyl = tm.creation.cylinder(
+                radius=self.motor_hole_diameter / 2,
+                height=self.thickness + 0.2,
+                sections=32,
+            )
+            rot = tm.transformations.rotation_matrix(pi / 2, [1, 0, 0])
+            cyl.apply_transform(rot)
+            cyl.apply_translation([x_off, hole_y, hole_z])
+            holes.append(cyl)
+
+        # Motor shaft clearance
+        shaft = tm.creation.cylinder(
+            radius=self.shaft_clearance_diameter / 2,
+            height=self.thickness + 0.2,
+            sections=32,
+        )
+        shaft.apply_transform(tm.transformations.rotation_matrix(pi / 2, [1, 0, 0]))
+        shaft.apply_translation([self.base_length / 2, hole_y, hole_z])
+        holes.append(shaft)
+
+        bracket = safe_difference(bracket, holes)
+        return bracket
+
+    def mesh(self) -> tm.Trimesh:
+        return self._mesh.copy()
+
+    def at(self, x: float, y: float, z: float) -> "RightAngleMotorBracket":
+        self._mesh.apply_translation([x, y, z])
+        return self