OpenModelica — The Complete Guide: Free Modelling and Simulation of Physical Systems
OpenModelica is an open-source modelling and simulation environment for the Modelica language — an open language for describing physical systems with equations. Instead of thinking in input-output signal blocks (as in Simulink), you connect physical components — a resistor, motor, gearbox, pipe, heat exchanger — and the software assembles and solves the equations itself.
OpenModelica
Open Source Modelica Consortium
Simulate multi-domain physical systems with the Modelica language.
Get it from the vendorWhy it is different
Modelica modelling is acausal: a component doesn't "know" what goes in and what comes out, only the physical relationship between its variables. So you can connect an electrical system to a mechanical and a thermal one exactly as it is built in reality — which makes models of complex systems readable and easy to change.
What is in OpenModelica
- OMEdit — a graphical editor: drag components from the library, connect them, set parameters and run.
- Modelica Standard Library — components for electrical, translational and rotational mechanics, multibody systems, heat, fluids and control.
- Results — plots of any variable over time, and comparison between runs.
- FMI — export and import of model units (FMU) for co-simulation with other tools.
What's missing
Specialised commercial libraries (for automotive or advanced HVAC systems, for example) are mainly available in paid tools such as Dymola. Very large models can be slow to compile and solve, and error messages about unbalanced equations take experience to understand. The interface is less polished than commercial tools.
Who it suits
Systems, mechanical and electrical engineers, designers of energy and control systems, researchers, and students learning system dynamics.
Alternatives and companion tools
For Simulink-style block simulation — Scilab with Xcos. For general numerical computing — GNU Octave or Python. And for multidisciplinary system optimisation — OpenMDAO.
Scilab
Dassault Systèmes / Scilab Enterprises
Numerical computing with Xcos — block-diagram simulation of dynamic systems alongside scripting.
Get it from the vendor
GNU Octave
GNU Project
Numerical computing in MATLAB-compatible syntax — matrices, equations, signals and plots.
Get it from the vendor
Python
Python Software Foundation
The language behind most modern engineering computation, and its full ecosystem.
Get it from the vendor
OpenMDAO
NASA Glenn Research Center
A framework for multidisciplinary optimisation, from NASA.
Get it from the vendorBottom line
If you need to simulate a real physical system spanning several domains, OpenModelica gives you the professional modelling language for free.