I'm working on a racing game with realistic racing car physics that's all custom written, however I still use off the shelf physics engines for everything except for the tyres/sprints/aerodynamics The rigid body simulation and collision detection frameworks from existing engines are still extremely handy, meaning I just have to add some extra forces into the sim and it all works out of the box.

Do you mind if I briefly hijack this thread to ask what sort of collision resolution methods work well for racing games? Particularly given you need incredibly smooth movement over terrain...

Do you mind if I briefly hijack this thread to ask what sort of collision resolution methods work well for racing games? Particularly given you need incredibly smooth movement over terrain...

I don't know about Hodgman's approach, but the most widely used and easiest to implement seems to be the raycasting model. Shoot a ray from the wheel hub downwards to find the contact point, compute forces based on the suspension spring/dampening, steering, wheel rpm, slip angle, tire model, etc. you can get as crazy as you like.