The drive loop was armed purely edge-triggered from
humanoid:GetPropertyChangedSignal("SeatPart") plus a one-shot catch-up
applySeat() at init. On cold boot the server seats the player AFTER that
catch-up runs, so the edge is lost, startDriving() never connects, and all
four wheel motors stay at MotorMaxTorque = 0 - the car is completely
undrivable until the player manually gets out and back in.
Replace the one-shot with a 0.5s level-triggered watchdog: if seated in a
DriveSeat with no live heartbeat connection, arm it; if not seated with a
live connection, stop it. Immune to any ordering of bootstrap vs seating.
Verified on cold boot (no manual reseat): all 4 motors uniform, poisoned
torque values restored within 0.6s, car accelerates to MaxSpeed 163 studs/s,
holds it upright, and engine-brakes 163 -> 0.
- New shared Chassis.luau: geometry constants + per-car tuning from stats
- CarManager.buildCarModel rebuilt: prismatic+spring suspension per corner,
servo-hinge steering on front knuckles, motor-hinge driven wheels,
hidden dense ballast for anti-roll; VehicleSeat kept as input device only
- New client ChassisController: drives motors/servos from seat
ThrottleFloat/SteerFloat per Heartbeat; speed-sensitive steering lock;
engine braking on throttle release
- Driver gets network ownership of every unanchored part (constraint
assemblies are separate; missing one causes stuttery physics)
- Docs: MESH_SWAP.md rewritten for shell-on-chassis workflow; ROADMAP updated
jesse