From FreeCAD Documentation
- Select the Solver object in the Tree view, e.g., for CalcuilX solver SolverCcxTools.
- There are several ways to invoke the command:
- Press the Solver job control button.
- Select the Solve → Solver job control option from the menu.
- Use the keyboard shortcut: S then T.
- Optionally, edit working directory.
- Optionally, select analysis type.
- Click Write .inp file to write the input file.
- Optionally, click Edit .inp file.
- Input file will open so you can edit it and save by Ctrl+S.
- Click Run CalculiX to trigger the solver.
- The solution may take considerable time for large models.