The use of Open Dynamics Engine in Xpand Rally to achieve fully dynamic and interactive environment of track also resulted in correct and realistic simulation of car damage.

The parameters of all objects in the game are fully configurable so it is possible to set their various features individually, like: coefficients of friction, elasticity, number of degrees of freedom, maximum velocities and many others. That makes all objects surrounding the tracks have individual influence on the car during a collision depending on their physical parameters. A good example are plastic posts frequently placed on the road shoulders that can be easily "moved down" by the car. Although it depends on the velocity of the car the influence on its damage will remain insignificant. It will be limited to impactions of bumpers, sometimes the bonnet or only to scratches of the paint when we hit the post with the side of the car. Road signs are a similar case but adequately to their physical properties they will have some more influence on the car. The signs are much heavier and harder which makes the forces affecting the car during a collision cause more damage. All drivers know about those dependencies on the roads and having the choice between "moving" a plastic post or a road sign they will choose the first option taking care of their cars and health. We were able to move these intuitional drivers' feelings into the game.

Because the car in Xpand Rally with its mass and velocity is subject to all physical laws known from the real world, analogically to the previous example just like in real life it will be much better to hit a road sign than a tree. Such examples can be given endlessly with regard to fences, low walls and finishing on buildings.
As it is now clear what mechanism and rules cause car damage lets discuss the damages themselves. In Xpand Rally the possible damage types are:

• mentioned before scratches of the paint
• damage of the body of the car, such as:
  • impactions and partial or full detachments of bumpers
  • full and partial detachments of spoilers
    impactions of: wings, doors, bonnets, roof
  • full and partial detachments of doors and bonnets
  • cracking and full breaking of glasses in all windows
  • damage of reflectors and wipers
• damage of suspension and brakes
  • ripping tyres and their loss
  • flapping wheels and their detachment
  • damage of springs and dampers
  • damage of stabilizers
  • damage of brakes of separate wheels
• damage of engine and transmission system
  • damage of the cooling and lubrication system resulting in engine overheating and seizing
  • damage of the turbine influencing the power of the engine
  • damage of the engine decreasing its power and finally stopping the vehicle
  • damage of the clutch and gearbox eliminating gears or impeding their usage

In the game all damage is shown either by direct visualization if it's possible (e.g. body of the car) or by HUD display and indicators of: engine temperature, suspensions and steering system, brakes, transmission and engine, turbocharger and electrics.

Besides of damages that are results of collisions most of parts important to car handling undergo the simulation of wearing due to exploitation. Thus drivers preferring spectacular drives with long side slides and often blocking wheels will have to more often invest in changing tyres. The wearing of parts has special meaning for both driving the car and the economical layer of the game. It's forth to add that the system of parts wearing simulation features elements of risk management. Players that drive cleanly and effectively, not damaging the cars much and so being able to repair them inexpensively will more likely successfully finish a race. However each who risks driving a strongly impaired car can expect malfunctions being results of wearing various parts that will either make the driving much harder or even make it impossible to finish a race.

Driver's injuries system is a completely new element in rally games. The HUD in the game displays the driver's physical condition. During subsequent collisions not only the car is damaged but also driver's injuries are simulated and symbolically visualized as the change of color of various parts of the indicator. The health condition of the driver has direct impact on his reactions to sudden situations on the road and to how efficiently he handles the car. Head injuries can cause blurred vision that will surely affect driver's judgments and his reaction time. Limbs injuries can cause altered reactions to the attempts of turning, accelerating or braking. It is analogical to a true life situation where a driver complaining about his shoulder aching would manipulate the driving wheel in limited range or slower. The intention of the developers of the game the driver's injuries simulation system is about to increase the effect of realism of Xpand Rally.