nhf/touhou/houjuu_nue/joints.py

@@ -63,6 +63,7 @@ class ShoulderJoint(Model):
     axis_rotate_top: float = -225.0
 
     directrix_id: int = 0
+    angle_neutral: float = 10.0
 
     def __post_init__(self):
         assert self.parent_lip_length * 2 < self.height
@@ -189,8 +190,8 @@ class ShoulderJoint(Model):
         )
         theta = self.torsion_joint.spring.angle_neutral - self.torsion_joint.rider_slot_span
         loc_rotate = Cq.Location((0, 0, 0), (1, 0, 0), 180)
-        loc_axis_rotate_bot = Cq.Location((0, 0, 0), (0, 0, 1), self.axis_rotate_bot)
-        loc_axis_rotate_top = Cq.Location((0, 0, 0), (0, 0, 1), self.axis_rotate_top)
+        loc_axis_rotate_bot = Cq.Location((0, 0, 0), (0, 0, 1), self.axis_rotate_bot + self.angle_neutral)
+        loc_axis_rotate_top = Cq.Location((0, 0, 0), (0, 0, 1), self.axis_rotate_top + self.angle_neutral)
         result = (
             Cq.Assembly()
             .add(core, name="core", loc=Cq.Location())

nhf/touhou/houjuu_nue/wing.py

@@ -93,6 +93,8 @@ class WingProfile(Model):
         self.wrist_s = math.sin(self.wrist_theta)
         self.wrist_top_x, self.wrist_top_y = self.wrist_to_abs(0, self.wrist_height)
 
+        self.shoulder_joint.angle_neutral = -self.shoulder_angle_neutral
+
     @submodel(name="shoulder-joint")
     def submodel_shoulder_joint(self) -> Model:
         return self.shoulder_joint
@@ -180,6 +182,17 @@ class WingProfile(Model):
             #)
         )
 
+    @property
+    def shoulder_angle_neutral(self) -> float:
+        """
+        Returns the neutral angle of the shoulder
+        """
+        dx = self.shoulder_mid_x - self.shoulder_tip_x
+        dy = -(self.shoulder_mid_y - (self.shoulder_tip_y - self.shoulder_width))
+        result = math.degrees(math.atan2(dy, dx))
+        assert result >= 0
+        return result
+
     @target(name="profile-s0", kind=TargetKind.DXF)
     def profile_s0(self) -> Cq.Sketch:
         tip_x = self.shoulder_tip_x
@@ -270,10 +283,17 @@ class WingProfile(Model):
     def surface_s0(self, top: bool = False) -> Cq.Workplane:
         base_dx = -(self.base_width - self.base_plate_width) / 2
         base_dy = self.base_joint.joint_height
+        sw = self.shoulder_width
 
         axle_dist = self.shoulder_joint.parent_lip_ext
+        theta = math.radians(self.shoulder_joint.angle_neutral)
+        c, s = math.cos(-theta), math.sin(-theta)
         tags = [
-            ("shoulder", (self.shoulder_tip_x + axle_dist, self.shoulder_tip_y - self.shoulder_width), 0),
+            # transforms [axle_dist, -sw/2] about the centre (tip_x, tip_y - sw/2)
+            ("shoulder", (
+                self.shoulder_tip_x          + axle_dist * c + (-sw/2) * s,
+                self.shoulder_tip_y - sw / 2 - axle_dist * s + (-sw/2) * c),
+             self.shoulder_joint.angle_neutral),
             ("base", (base_dx,  base_dy), 90),
         ]
         result = nhf.utils.extrude_with_markers(