SIMRunning Simulations
Run FastSim
Run a circuit-based FastSim simulation from vehicle, circuit, ambient, and driver inputs.
FastSim is the circuit-based simulation type in 4ACE SIM. Use it when you need to simulate a vehicle around a selected circuit with a selected driver and ambient condition.
Before you start
- Select the correct team.
- Confirm the team has enough credits.
- Prepare a vehicle, circuit, ambient, and driver.
- Use FastSim when the run needs circuit distance, laps, and circuit-based analysis.
Run FastSim
- Open Simulations from the sidebar.
- Select New.
- In General, choose FastSim.
- Add Name, Notes, or Tags when useful. If name is blank, 4ACE can generate one from selected circuit and vehicle.
- Continue to Setup.
- Select Vehicle.
- Select Circuit. Team circuits and public circuits can appear in this selector.
- Select Ambient.
- Select Driver.
- Continue to Settings.
- Review Credit Consumption in the sheet header.
- Set simulation settings.
- Optional: turn on Save these settings as team defaults.
- Select Add simulation.
The run appears in the Simulations table after submission.
FastSim settings
| Setting | What it controls | Default | Validation / Range |
|---|---|---|---|
| Step Time (s) | Solver step time. | 0.01 | 0.001 to 0.01. Options: 0.01, 0.005, 0.002, 0.001. |
| Export Rate (Hz) | Telemetry export rate. | 100 | Options: 10, 100, 1000. |
| Solver Type | Numerical solver. | RungeKutta4 | Euler, RungeKutta2, RungeKutta3, RungeKutta4, DormandPrince45, ImplicitMidpoint, RadauIIA5. |
| Start Velocity (km/h) | Vehicle speed at simulation start. | 0 | Must be 0 or greater. |
| Start Gear | Gear at simulation start. | 1 | 1 to the selected vehicle's gear count, up to 8. |
| Simulation Length | Whether FastSim uses laps or duration. | Number of Laps | Laps or Duration. |
| Number of Laps | Lap count when lap mode is selected. | 1 | 1 to 100. |
| Duration (s) | Simulation time when duration mode is selected. | 5 | 5 to 7200. |
| Start Position (m) | Start distance around the circuit. | 0 | Must be 0 or greater. |
| Brake to Throttle Threshold | Transition threshold for FastSim driving behavior. | 0.5 | 0.1 to 0.99. |
| Brake Point Initial Shift | Initial brake point offset. | 0 | 0 to 1000. |
| Throttle Increment (%) | Increment used during throttle search. | 0.5 | 0.1 to 5. |
| Brake Increment (%) | Increment used during brake search. | 0.5 | 0.1 to 5. |
Check the result
- Open the simulation from the Simulations table.
- Wait for status to reach Completed.
- Open Summary to review performance metrics and lap data.
- Open Analysis to inspect telemetry and compare runs.
- Open Configuration when you need to confirm which vehicle snapshot, circuit, ambient, and settings were used.
Performance metrics appear only after the simulation completes successfully.
Troubleshooting
| Problem | What to check |
|---|---|
| Cannot continue from Setup | FastSim requires Vehicle, Circuit, Ambient, and Driver. |
| Credit consumption shows 0 or no estimate | Select Vehicle, Circuit, and Ambient first. |
| Number of laps error | Use 1 to 100 laps. |
| Duration error | Use 5 to 7200 seconds when duration mode is selected. |
| Start gear options stop before 8 | The selected vehicle has fewer available gears. |
| Performance metrics are missing | Wait for Completed status. Failed, pending, running, canceled, or timed-out runs do not show completed metrics. |
| Analysis has no data | Confirm the run completed and has telemetry output. |