Physics: VehicleSpec

In a pack: the physics section of vehicles/<name>.json, the field names the table's first column, any left out keeping the T15's; angles in degrees, speeds in km/h, steerGrip in g, the rest model frame and SI (kg, N, m, s, rpm). In Java: start from VehicleSpec.fromT15(), change it, build(), all SI and radians.

Field	Meaning	White-box coupe
mass	kerb mass, kg	1500
ix iy iz	moments of inertia about the three axes, kg·m²	2000 / 2300 / 520
comY comZ	centre of mass height and fore-aft position	0.48 / 0.05
frontZ rearZ	the axles' Z (front negative; their difference is the wheelbase)	−1.30 / 1.30
halfTrack	half the track	0.74
radius	tyre radius (245/45 R17 ≈ 0.33)	0.33
bump droop	suspension travel up and down	0.08 / 0.10
springFront/Rear dampFront/Rear	per wheel: spring rate N/m, damping N·s/m	36000 / 38000, 2700 / 2900
antiRollFront/Rear	anti-roll bars	22000 / 12000
maxSteer	front wheel lock	34°
steerGrip	tyre side grip (an acceleration)	0.95 g
topSpeed	top speed, m/s	230 km/h
torqueRpm torqueNm	the torque curve (pairs)	V8
idleRpm cutRpm stallRpm	idle, cut-off, stall	750 / 6300 / 400
starterTorque starterRpm	the starter	90 / 250
startFlare	the flare as it fires (rpm above idle): held 0.3 s, then falling back to idle over about a second, a sports car's bark at start-up, heard from the engine's own loops; 0 for none	0
preheat	a diesel's glow time (s); 0 for petrol	0
gears reverseGear finalDrive	gear ratios, reverse, final drive	5-speed manual
clutchTorque	the torque the clutch carries	600
automatic	an automatic: it picks its forward gears; the shift keys become paddles that hold a gear for 6 s	false
allWheel	all-wheel drive all the time (no transfer case; the drive split by the wheels' loads)	false
tractionControl	traction control: the throttle eased while a driven wheel spins	false
stabilityControl	stability control: the tail sliding out takes the throttle off and brakes the outer front wheel	false
electricParkingBrake	an electric parking brake: pulled while moving it brakes all four wheels with ABS, no rear wheels locked; standing it holds as usual. The speedometer reads all four wheels	false
fourWheelSpeed	the top speed for engaging 4WD; 0: rear drive only, no transfer case	0
lowRange lowRangeSpeed	low-range ratio and its speed limit (1 and 0 for rear drive)	1 / 0
brakeForce brakeFront	total brake force, front share	16000 / 0.62
rolling drag	rolling resistance, air drag	0.013 / 0.45
fuelPerKwh fuelIdle	fuel use	0.30 / 0.8
hull	the body's contact points (rolling over, walls, other vehicles); see below	boxHull(...)

In a pack "hull": {"box": [halfWidth, frontZ, rearZ, bottom, belt, cabinHalfWidth, cabinFrontZ, cabinRearZ, roof]} (Java: VehicleSpec.boxHull(...), the same nine) makes one: the lower body a box, the cabin a smaller box on it.