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/README.md

@@ -3,12 +3,16 @@
 A six-legged walking robot (Teensy 3.6) and its handheld remote
 (Teensy 4.1 + Nextion touchscreen), linked over nRF24L01.
 
+![The hexapod, OpenSCAD model in its standing pose](hardware/openscad/renders/hexapod.png)
+![The remote, OpenSCAD model](hardware/openscad/renders/remote.png)
+
 ```
 robot/                     robot firmware: IK, gait, body pose, IMU stabilization, state machine
 remote/                    remote firmware: 2 x 3-axis sticks, MPU6050 tilt, Nextion UI, RF24 TX
 shared/                    HexapodProtocol: the CmdPacket wire format + radio settings used by both
 sim/                       the unchanged robot firmware compiled into a DLL for the simulation
 Hexapod_Simulation_Unity/  Unity project that runs that DLL on the 3D model
+hardware/openscad/         OpenSCAD model of the robot and remote, rebuilt from the Fusion designs
 hardware/fusion360/        Fusion 360 designs: body, legs, servo, servo horn, remote case
 scripts/                   PlatformIO helper (per-environment sketch folder)
 ```