btVehicleTuning parameter units

[max1799]

btRaycastVehicle allows tuning some parameters of the vehicle like the suspension stiffness using the btVehicleTuning class. However it is unclear to me what units these tuning parameters use:

Code: Select all

	class btVehicleTuning
	{
	public:
		btVehicleTuning()
			: m_suspensionStiffness(btScalar(5.88)),
			  m_suspensionCompression(btScalar(0.83)),
			  m_suspensionDamping(btScalar(0.88)),
			  m_maxSuspensionTravelCm(btScalar(500.)),
			  m_frictionSlip(btScalar(10.5)),
			  m_maxSuspensionForce(btScalar(6000.))
		{
		}
		btScalar m_suspensionStiffness;
		btScalar m_suspensionCompression;
		btScalar m_suspensionDamping;
		btScalar m_maxSuspensionTravelCm;
		btScalar m_frictionSlip;
		btScalar m_maxSuspensionForce;
	};

E.g. I expected the suspensions stiffness to be specified in N/m. However this does not appear to be the case. What are the units used for these parameters?

[max1799]

It appears those parameters are weighted by the chassis mass, so e.g. `suspensionStiffness` has the unit `N/chassisMass`.