SIMVehicles
Polynomials
Understand 1D and 2D polynomial parameters used by vehicle submodules in 4ACE SIM.
Polynomials define coefficient-based curves for module parameters that support polynomial mode. Use them when a constant value is too simple and a lookup table is not the preferred input format.
Polynomial types
| Type | Coefficients | Formula | Notes |
|---|---|---|---|
| 1D polynomial | c0, c1, c2, c3 | y = c0 + c1*x + c2*x^2 + c3*x^3 | Used for one input axis. Some rows fix c0 at 0. |
| 2D polynomial | c0, c1, c2, c3, c4, c5 | z = c0 + c1*x + c2*y + c3*x*y + c4*x^2 + c5*y^2 | Used for two input axes. |
How polynomial rows work
- Open a module detail page.
- Find a method row such as aero ride height method or steering angle method.
- Select Polynomial when available.
- Edit the polynomial coefficient row.
- Use the info dialog or chart preview to inspect the curve.
- Save with Update Data.
Rows that belong to inactive methods are dimmed in the parameter table. Rows marked FIXED.c0 keep c0 at 0.
Supported polynomial previews
| Module | Parameter | Dimension | Preview axes |
|---|---|---|---|
| Aerodynamics | Ride height Cd polynomial | 2D | Ride Height Front (mm), Ride Height Rear (mm), Cd |
| Aerodynamics | Ride height Clf polynomial | 2D | Ride Height Front (mm), Ride Height Rear (mm), Clf |
| Aerodynamics | Ride height Clr polynomial | 2D | Ride Height Front (mm), Ride Height Rear (mm), Clr |
| Aerodynamics | Speed Cd polynomial | 1D | Vehicle Speed (m/s), Cd Delta |
| Aerodynamics | Speed Clf polynomial | 1D | Vehicle Speed (m/s), Clf Delta |
| Aerodynamics | Speed Clr polynomial | 1D | Vehicle Speed (m/s), Clr Delta |
| Aerodynamics | Yaw Cd polynomial | 1D | Yaw Angle (deg), Cd Delta |
| Aerodynamics | Yaw Clf polynomial | 1D | Yaw Angle (deg), Clf Delta |
| Aerodynamics | Yaw Clr polynomial | 1D | Yaw Angle (deg), Clr Delta |
| Drivetrain | Engine intake pressure vs speed polynomial | 1D | Car Speed (m/s), Intake Pressure (Pa) |
| Steering | Steer angle vs rack travel polynomial left | 1D | Rack Travel (mm), Steer Angle (deg) |
| Steering | Steer angle vs rack travel polynomial right | 1D | Rack Travel (mm), Steer Angle (deg) |
| Steering | Camber angle vs steer angle polynomial left | 1D | Steer Angle (deg), Camber Angle (deg) |
| Steering | Camber angle vs steer angle polynomial right | 1D | Steer Angle (deg), Camber Angle (deg) |
| Suspension | Toe vs wheel travel polynomial left | 1D | Wheel Travel (mm), Toe Angle (deg) |
| Suspension | Toe vs wheel travel polynomial right | 1D | Wheel Travel (mm), Toe Angle (deg) |
| Suspension | Camber vs wheel travel polynomial left | 1D | Wheel Travel (mm), Camber Angle (deg) |
| Suspension | Camber vs wheel travel polynomial right | 1D | Wheel Travel (mm), Camber Angle (deg) |
| Suspension | Front view swing arm angle polynomial left | 1D | Wheel Travel (mm), Front View Swing Arm Angle (deg) |
| Suspension | Front view swing arm angle polynomial right | 1D | Wheel Travel (mm), Front View Swing Arm Angle (deg) |
Dynamic chart ranges
Some previews compute chart ranges from other values in the same module:
- Aerodynamic ride-height polynomial range uses frontal area.
- Steering camber-angle polynomial range uses rack travel max and steer angle behavior.
- Suspension kinematic polynomial range uses unsprung CoG height.
If those source values are missing or invalid, the polynomial preview cannot resolve the chart range.