# 9. Graphical Modelling

OMSimulator has an optional dependency to OpenModelica in order to utilize the graphical modelling editor OMEdit. This feature requires to install the full OpenModelica tool suite, which includes OMSimulator. The independent stand-alone version doesn’t provide any graphical modelling editor.

Composite models are imported and exported in the System Structure Description (SSD) format, which is part of the System Structure and Parameterization (SSP) standard.

See also FMI documentation and SSP documentation.

OMEdit MainWindow and Browsers.

## 9.1. New SSP Model

A new and empty SSP model can be created from File->New->SSP menu item.

OMEdit: New SSP Model

That will open a dialog to enter the names of the model and the root system and to choose the root systems type.

There are three types available:

  - TLM - Transmission Line Modeling System

  - Weakly Coupled - Connected Co-Simulation FMUs System

  - Strongly Coupled - Connected Model-Exchange FMUs System

OMEdit: New SSP Model Dialog

OMEdit: Newly created empty root system of SSP model

## 9.2. Add System

When a new model is created a root system is always generated. If you need to have another system in your root system you can add it with SSP->Add System.

For example only a weakly coupled system (Co-Simulation) can integrate strongly coupled system (Model Exchange). Therefore, the weakly coupled system must be selected from the Libraries Browser and the respective menu item can be selected:

OMEdit: Add System

That will pop-up a dialog to enter the names of the new system.

OMEdit: Add System Dialog

## 9.3. Add SubModel

A sub-model is typically an FMU, but it also can be result file. In order to import a sub-model, the respective system must be selected and the action can be selected from the menu bar:

OMEdit: Add SubModel

The file browser will open to select an FMU (.fmu) or result file (.csv) as a subsmodel. Then a dialog opens to choose the name of the new sub-model.

OMEdit: Add SubModel Dialog

OMEdit: Root system with added FMU.

## 9.4. Simulate

Select the simulate button (symbol with green arrow) or select Simulation->Simulate from the menu in OMEdit to simulate the SSP model.

## 9.5. Dual Mass Oscillator Example

The dual mass oscillator example from our testsuite is a simple example one can recreate using components from the Modelica Standard Library. After splitting the model into two models and exporting each as an Model-Exchange and Co-Simulation FMU.

Dual mass oscillator Modelica model (diagramm view) and FMUs

OMEdit: Simulate Dual Mass Oscillator SSP model