Some of this variable can change on my next version because I use it only for my personal debug.
// I remove some of this variable on my next version...
// It define the matrix row to apply my value.
int chassisAxis, int tractionAxis, int steerAxis, int frictionAxis,
ChassisAxis{ caFront, caUp, caRight }; Default value 1 this is use with local matrix to define the tire working space.
TractionAxis{ taFront, taUp, taRight }; Default value 0 this is use to apply the engine force and torque at the good side.
SteerAxis{ saFront, saUp, saRight }; Default value 2 this is use to apply the steer force and torque at the good side.
FrictionAxis{ faFront, faUp, faRight }; Default value 2 but this one is removed internally now, not use anymore...
The springConst and springDamper is really personal to your vehicle.
It depending from your vehicle mass and the world gravity and more...
Generally I play with springConst value around 30 to 150, the springDamper is really personal and depending from the Const and your personal choice.
Exemple a Const set to 70 can look natural with a damp around 4 or 5, but again it depending from the vehicle type and the vehicle mass.
castMode value 0 the vehicle use the raycast world internally for generate the tire, value 1 use the convexcast internally for generate the tire.
chassisOmegaCorrection avoid rotation on the vehicle chassis.
The value play around 0.1 to 1, exemple you have a long vehicle chassis you can need to use high value like 0.995 the default is 0.98.
If you have a short vehicle chassis you need to reduce the value exemple 0.95 or lower.
This fake the slipping reaction in same time, just to make some test with this value.
The way how work the engineforce can change later, it is a static value use at the vehicle construction.
I have add it because I have rewrite this code from a personal pascal project and at the begin I have implement it same.
Now it can need a work around to make it better.
oxDGRaycastVehicleSetVar(FData,FChassisOmegaCorrection,FChassisEngineForce,FChassisSteerForce);
My current default value is 0.98,40,60 call oxDGRaycastVehicleSetVar at the begin when the vehicle and tire is already create.
This method can change later...
Will it work right if I just increment a value when a key is pressed, or do I have to do something more complicated?
It's a little bit more complicated.
Take a look on this file in coming with my demo.
oxN2VehicleWorldRaydll.pas
It is very similar to the multibodyvehicle method, I can make something a lot more simple on next version.
I working on the vehicle code today and try to update it soon with some new nice fix.
I know what you need about the way to apply steer and engine I try to make it simple today and I update the code on the night.
Sorry if it is not all clear but you need to understand it is again in construction and many thing can change in futur version.