Hopsan is a free simulation environment for fluid and mechatronic systems, developed at Linköping University.

A separate tool called COMPGEN, written in Mathematica, was also developed, which can be used to generate component models in a more straightforward way.

[4] The current generation of Hopsan consists of two parts, a graphical user interface and a simulation core library.

This includes components for hydraulic, pneumatic, electrical, mechanical and control systems (filters, non-linear functions and arithmetic).

Numerical optimization can be performed by a built-in tool, using COMPLEX-RF, COMPLEX-RFP or particle swarm algorithms.

The transmission line element method is very suitable for parallel execution, due to physically motivated time delays between certain components.

[6] Features in the graphical user interface include Python scripting, an undo/redo function, XML-based model and configuration files, hydraulic symbols according to the ISO 1219-1 standard and global system parameters that can be shared between components.