BobSim Startup Problems

Find the symptom, then apply the fix. Run the commands from the BobSim repository root.

BobLib submodule missing

make init

make app or another target fails with a Docker error

Make sure that Docker is running and that docker compose version works. Then build the image again:

make docker-build

The app page does not load

Open http://127.0.0.1:8765, not the 0.0.0.0 address that the container prints. If another program already uses port 8765, start the app with make app APP_PORT=8766 and open that port.

Simulation is locked

Hover over the locked control. It names the reason. The app wants these in order:

1. The vehicle is saved.
2. The vehicle is written to MBD.
3. The OpenModelica toolchain is verified.

In Docker the toolchain is always present. On the host, see Run BobSim Without Docker.

No module named yaml

You started the app on the host with RUN=, without the dependencies. Install them into the same interpreter:

python -m pip install -r requirements.txt

Toolchain saved but a library is reported missing

This happens on the host only. The library directory does not contain that library. Make sure that Library directory points at the folder that installPackage wrote to, and install the exact versions.

A run failed and you want the raw directory

The directory is already there. All four shipped configs set execution.cleanup: false, so BobSim keeps run directories under the build directory:

_3_StandardSim/BuildBobLib/VehicleSim/results/run_<id>/
_3_StandardSim/BuildBobLib/FourPostSim/results/run_<id>/

If results/ is not writable, BobSim writes to runs/ in the same build directory instead.

Each run directory holds run.log, overrides.txt, the raw result CSV, and a manifest. If the directory is gone, something set execution.cleanup: true. Check the app's copy in _5_App/user_data/config/active/ first, then the checked-in config. Set it back to false and run again.

Files in the checkout belong to root

On Linux, files written from the container belong to root. make clean-owned deletes the generated results and app data through the container, so you do not need sudo.

You want to start the app from a clean state

This command deletes saved vehicles, configs, toolchain settings, workspaces, the build cache, and archive packages in _5_App/user_data/:

make clean-app

Next Pages

• BobSim App troubleshooting for problems inside the app views
• BobSim Use Guide to debug a failed run