SIMRunning SimulationsOpenSim
Run OpenSim
Run an OpenSim simulation using vehicle, ambient, driver, and Driver Input timelines.
OpenSim is the open simulation type in 4ACE SIM. It does not use a circuit selector. Instead, it uses a Driver Input that prescribes throttle, brake, steer angle, and optional gear timelines.
Use OpenSim when you need to test a vehicle response against known control traces rather than a full circuit lap.
Before you start
- Select the correct team.
- Confirm the team has enough credits.
- Prepare a vehicle, ambient, and driver.
- Create a Driver Input for the control timeline.
Run OpenSim
- Open Simulations from the sidebar.
- Select New.
- In General, choose OpenSim.
- Add Name, Notes, or Tags when useful.
- Continue to Setup.
- Select Vehicle.
- Select Ambient.
- Select Driver.
- Select Driver Input.
- Review the Driver Input preview.
- Continue to Settings.
- Review Credit Consumption in the sheet header.
- Set the shared simulation settings.
- Optional: turn on Save these settings as team defaults.
- Select Add simulation.
When you switch to OpenSim, the circuit selection is cleared because OpenSim does not use a circuit input.
OpenSim 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. |
| Duration (s) | Simulation duration. | Driver Input duration | Set from the selected Driver Input timeline and disabled in the form. |
OpenSim uses the end time of the selected Driver Input as the simulation duration.
Driver Input preview
The setup step shows a preview after you select a Driver Input:
- Timeline length.
- Gear mode: model-handled or specified by Driver Input.
- Number of visible channels.
- Charts for throttle, brake, steer angle, and gear when gear is enabled.
Check the result
- Open the simulation from the Simulations table.
- Wait for status to reach Completed.
- Open Summary for metadata, resource usage, and performance data when available.
- Open Analysis to inspect telemetry.
- Open Configuration to confirm selected inputs and settings.
Troubleshooting
| Problem | What to check |
|---|---|
| No Driver Inputs yet | Select Create Driver Input in setup, or open Driver Inputs from the sidebar. |
| Cannot continue from Setup | OpenSim requires Vehicle, Ambient, Driver, and Driver Input. |
| Duration cannot be edited | OpenSim duration is set by the selected Driver Input timeline. |
| Credit consumption shows 0 or no estimate | Select Vehicle and Ambient first. |
| Analysis has no data | Confirm the run completed and has telemetry output. |