Vehicle Dynamics: Center of Gravity and Anisotropic Tire Friction?

[jwatte]

Have you tried playing with the inertia tensor of the car? Specifically along the x-axis?

I have not played with this – is it by default something scary, like infinite?
The behavior I’m seeing seems to be self-righting, though – the car seems to have a center of gravity that is below the ground; it rotates unnaturally.

I suspect that when the tires are still touching the ground there might be some bad behavior caused by the fact that the tires are using a simple ray cast and (perhaps) don’t consider the tire’s tipping point.

Rays can generate fantastic driving simulation, if you do some work to properly simulate an anisotropic contact patch and suspension forces, and put the center of gravity of the car a little bit above the tire contact plane.
If you think of the ground contact as a plain contact, with very low friction in the direction the tire is pointed (or even a linear motor in that direction) and much higher friction (but some slip) in the sideways direction, “tipping” simply happens when the sideways force from the center of gravity of the chassis moving into the turned wheel is enough to lift/twist the car.
The ODE library contact joint with linear motor support is perfect for this (because it solves in velocity space); I don’t know how detailed you can get with contact joints/patches in PhysX?
I’ll see if I can get a recording of the behavior I mean.