2026: OpenSCAD robot and remote, physical joint limits, model in Unity

hardware/openscad/ rebuilds the broken Fusion models as OpenSCAD:
body (top/bottom plate, standoffs, battery bay, switch), legs (coxa
bracket, femur link, tibia, horn adapters, TPU socks, servo cables),
the whole robot, and the remote (shell, lid, Nextion 3.5", JH-D400X-R4
sticks, 18650 UPS board, IMU, Teensy 4.0, USB-C breakout). Every part
was checked by slicing against the original STEP solids; the original's
bugs are fixed and listed in PLANNING.md.

The robot now uses a hexagon leg layout (corner legs 60 deg round from
the mid legs; the corner coxa brackets need turning on their splines).
Physical limits from a collision sweep of the model are in Config.h:
per-leg coxa limits and LEG_CLEARANCE_MM 56 (a leg is 55.2 mm wide at
the joints); the sim API exports them (version 7). sim_smoke passes.

Unity loads the model (export_unity.py -> Resources/OpenScadModel,
OpenScadModel.cs builds a new rig in place of the old scene's robot).
The PCB model's mounting holes now use the exact EasyEDA grid. README
shows renders of both.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

2026-current/Hexapod_Simulation_Unity/Assets/HexapodSim/HexapodSimulation.cs

@@ -32,6 +32,9 @@ namespace HexapodSim
         public float unitsPerMm = 0.1f;
         [Tooltip("Firmware tibia angle when the rig's Knie rotation is 0 (tibia straight down from a horizontal femur).")]
         public float kneeRestDeg = -90f;
+        [Tooltip("Replace the old scene's robot with the OpenSCAD model (hardware/openscad, export_unity.py).")]
+        public bool useOpenScadModel = true;
+        bool openScadBuilt_;
 
         [Header("World")]
         [Tooltip("Tilts the ground (deg about robot X = roll, Y = pitch) to exercise the robot gyro.")]
@@ -123,6 +126,11 @@ namespace HexapodSim
                 Native.SetRadioPresent(radioPresent);
                 Native.SetImuPresent(imuPresent);
                 Geometry = Native.Geometry;
+                if (useOpenScadModel && !openScadBuilt_ && OpenScadModel.Available)
+                {
+                    OpenScadModel.Build(chassis, Geometry, forwardAxis, unitsPerMm);
+                    openScadBuilt_ = true;
+                }
                 BindRig();
                 Native.SetGroundTilt(groundTiltDeg.x, groundTiltDeg.y);
                 Native.Start();