I want to start learning physics engine by maing a simple car simulator. The question is, what kind of car model should I have? Should the car body and its tyres be a separated model? Because PH_WHEEL typed 'phconn_add' function seems to need a separated model.
Having a car model and 4 separate wheels connected by PH_WHEELs is the most straightforward solution. You could also just use one car model and then apply forces to it turning it into something more like a hovercraft.