Aerodynamics Module

AerodynamicsModule inspector.

Simulates aerodynamic drag and downforce forces on the vehicle.

Drag

Drag is calculated using the standard aerodynamic equation: F = 0.5 * rho * A * Cd * v^2

  • rho: Air density (1.225 kg/m³ at sea level)
  • A: Frontal or side area (calculated from vehicle dimensions)
  • Cd: Drag coefficient (Frontal Cd or Side Cd)
  • v: Velocity in the respective direction

Drag forces are calculated separately for:

  • Longitudinal (forward/backward motion): Uses Frontal Cd and frontal area (width * height * 0.85)
  • Lateral (side-to-side motion): Uses Side Cd and side area (height * length * 0.8)

Vehicle dimensions are configured under VehicleController > Settings tab (changed in v14).

Drag Coefficients

Typical Frontal Cd values (reference):

  • Sports cars: 0.25-0.35
  • Sedans: 0.3-0.4
  • SUVs/Trucks: 0.35-0.5
  • Buses/Large vehicles: 0.6-0.8

Typical Side Cd values: 0.8-1.5 (generally higher than frontal due to less aerodynamic profile).

Damage Integration

When the vehicle has a DamageHandler component, additional drag is applied based on damage:

  • Damage Drag Effect: Multiplier for extra drag when fully damaged (default: 0.5 = +50%)
  • Scales linearly with damage level (0 to 1)
  • Simulates aerodynamic penalty from damaged bodywork

Performance

Forces are set to 0 when vehicle speed is below 1 m/s to avoid unnecessary calculations.

Downforce

Downforce is applied at configurable points on the vehicle to increase tire grip at high speeds.

  • Force increases quadratically from 0 to Max Downforce Speed, then remains constant
  • Formula: actualForce = maxForce * (speed / maxDownforceSpeed)^2
  • Not dependent on vehicle dimensions, only on configured points and speed

Downforce Points

Each point has:

  • Position: Local coordinates relative to vehicle transform
  • Max Force: Maximum force in Newtons at max downforce speed

Positioning guidelines:

  • Place points low on the vehicle (at wheel height or lower)
  • High positions create excessive pitch moments and handling instability
  • Typical setup: One point at front axle, one at rear axle
  • Front-biased: Reduces understeer at speed
  • Rear-biased: Improves stability

Force recommendations by vehicle type:

  • Street cars: 100-500 N per point
  • Sports cars: 500-2000 N per point
  • GT/Touring cars: 2000-5000 N per point
  • Formula/Race cars: 5000-10000+ N per point

Ensure suspension spring rates can handle maximum downforce to avoid bottoming out.

Visualization

Enable Gizmos to see downforce points as red spheres in the Scene view.

Properties

Property Description
Simulate Drag Enable/disable drag calculation (default: enabled)
Simulate Downforce Enable/disable downforce calculation (default: disabled)
Frontal Cd Coefficient of drag for frontal area (0-1)
Side Cd Coefficient of drag for side area (0-2)
Max Downforce Speed Speed in m/s where downforce reaches maximum value
Damage Drag Effect Additional drag multiplier when fully damaged (0-5)
Downforce Points List of positions and forces for downforce application
Longitudinal Drag Force Current forward/backward drag in Newtons (read-only)
Lateral Drag Force Current side-to-side drag in Newtons (read-only)