Car meshes:
- CarManager: clone ReplicatedStorage/CarModels/<carId> as a visual Shell,
weld to Body, hide placeholder blocks. Falls back to procedural CarBody
when no mesh exists, so cars can be converted one at a time.
- Shell parts are Massless/CanCollide=false/CanQuery=false: the constraint
chassis and driving feel are untouched. Verified 0 violating parts live.
- 5 catalogue cars mapped from the 67-model ServerStorage/CarLibrary import.
Suspension (ref docs/CAR_PHYSICS_REFERENCE.txt, devforum 3915628):
- BUG: old k=9000 gave 1.10 studs static sag against 0.90 studs total travel,
i.e. the suspension sat permanently bottomed out and the spring did no work.
- Stiffness now solved from a sag target (70%% of half travel); damping now
derived as a damping ratio c = zeta*2*sqrt(k*m) instead of an unrelated
constant. Old pair worked out to zeta=0.31 (floaty); now 0.55-0.63.
- Measured after fix: ride height 1.97 studs, bounce 0.000, body roll 0.002.
Also: Circuit.inPA square test (PAFloor is 520x520, test was a r=260 circle,
corners falsely reported outside and spuriously armed runs), and void-fall
recovery now moves the character to the spawn pad BEFORE building the car.
Hermes