Batch Mode
BurnSim 4 can run a simulation with no window at all: give it a motor file and somewhere to put the results, and it loads the motor, simulates it, writes the burn data as CSV and exits with a status code a script can test. This is how you sweep a parameter, re-run a set of designs after changing a propellant, or check motors from a build script.
It requires an activated personal or commercial license. It is not available on an educational license, or in trial/unlicensed mode.
Usage
BurnSim -infile <motor.bsx> -outfile <results.csv> [-units metric|imperial]
| Option | What it does |
|---|---|
-infile |
The .bsx motor file to simulate. Required.
|
-outfile |
Where to write the CSV. Required. This is the same time-step table File → Export CSV writes, minus the imported-test-data columns - a batch run has no way to supply a measured trace.
|
-units |
metric or imperial. Optional; without it the run uses your saved display-units setting.
|
-help (or -?) |
Print the usage text and exit. |
Both -infile and -outfile must be given. Supplying only one is an error rather than a silent fall-back to opening the window - a typo in one flag would otherwise leave a windowless BurnSim running on a build machine having written nothing.
A bare file path on its own does not trigger batch mode: that is how a double-clicked .bsx arrives, and it still opens normally in the GUI.
Exit codes
| Code | Meaning |
|---|---|
| 0 | Success - the CSV was written. |
| 1 | The simulation or file access failed. The input file was missing, or the design has a problem serious enough to stop the run. No CSV is written. |
| 2 | A usage error - a missing or unrecognized option, or a -units value that is neither metric nor imperial.
|
| 3 | The license does not cover batch mode (educational, trial, or unlicensed). |
Any design messages BurnSim would have shown in the Results panel are written to standard error, prefixed burnsim:. Warnings do not stop the run; a critical message does, and is the usual reason for exit code 1.
Waiting for the run to finish
This is the one thing that catches people out. BurnSim is a GUI program, and a shell does not wait for one of those - it returns to the prompt immediately, before the CSV exists and before the exit code is set. Read a result straight after the command and you will read a half-written file, or none.
Redirecting the output is what makes the shell wait:
BurnSim -infile motor.bsx -outfile results.csv | Out-Null # PowerShell BurnSim -infile motor.bsx -outfile results.csv > log.txt # cmd
Start-Process -Wait works too. On success the path of the CSV it wrote is printed to standard output.
See also
- BurnSim Fields - the same simulation, driven from the window
- Activating BurnSim - activating the license batch mode needs
- Import from CSV - going the other way, bringing measured data in