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Import FMU🔗

The FMU Import allows users to import models from other tools to be used in Modelon Impact. The Functional Mock-up Interface is a free standard that defines a container and interface for exchanging dynamic simulation models using a combination of XML files, binary files, and C code, distributed as a FMU file (a ZIP file). The acronym FMU stands for Functional Mock-up Unit. This unit/file contains the model to be exchanged.

For more information, please read also chapter FMUs.

FMUs can imported into Modelon Impact. During the import, Impact wraps the FMU in a Modelica class and store this class in your selected Modelica package. The FMU file itself is stored in the Resources folder of your package. See also chapter.


Impact only supports Co-Simulation.

  1. Go to the top of a Project panel located in left sidebar.
  2. Click on the upward pointing arrow for FMU Import.
  3. Select the .FMU file to be imported, and a dialog called IMPORT FMU* opens. In this dialog, you can (re-)define a Modelica class name and the target package.
  4. Click IMPORT and the FMU will be wrapped in a model class and stored in your package.
  5. Now, this new model is ready to be instantiated, opened, duplicated, or extended. Feel free to ad your own icon etc.


In the Import dialog you have the option "Overwrite existing FMU" which is checked by default, e.g. for importing a new version of an FMU. If you dont want to overwrite existing FMUs please uncheck this option.

Platform compatibility🔗

The imported FMU must be compliant with specific platforms in order to import successfully. This is primarily due to FMUs depending on glibc. Starting with Impact 2024.1, FMUs from the following platforms are supported:

  1. Ubuntu 20.04 or older
  2. CentOS 7 or any similar RHEL 7.x platform

With older versions of Modelon Impact, only FMUs from 2. above is supported.

Known limitations of FMU Import🔗

1. Duplicate FMU Import components:🔗

A model that uses duplicated FMU Import components may experience unexpected or strange simulation results. The workaround for this is to import the same FMU multiple times but under different names instead. For example, To duplicate an imported FMU three times, then the recommendation is to import the same FMU 3 times using different names.

2. Rename FMU Import components:🔗

Renaming a component generated via FMU Import will not break the behavior of a model but the component itself will lose references to files generated in its Resources directory. When an FMU is imported into a library, directories, and files are generated in the Resources directory relative to the name of the FMU. Therefore when a generated model is manually renamed, the relation to the files in the Resources directory is not maintained since those files are not automatically renamed when the generated model is renamed.
You can fix this by adjusting the file paths in the Modelica code.

3. Move FMU Import components:🔗

Moving a component generated via FMU Import to a different part of a library. For the same reason as in 2nd case above, this can make it difficult to identify which files in the Resources directory are related to the moved model.

4. Remove FMU Import Models:🔗

Removing a model generated via FMU Import. Same as in 2nd case and 3rd case above - FMU Import consists of two parts, the generated mo-file and the files added in the Resources directory. Removing one or the other will not automatically remove all the files that were generated during the import step.

5. Licensed FMUs:🔗

Licensed FMUs that have dependencies (like external license server) to third-party software/binaries that are distributed outside the Modelica library are currently not supported.

Couldn't Import FMU on Impact?

Import Package|Export FMU|Import Workspace