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Stable 73

This version was released on 2021-MAR-23

Updated user features🔗

  1. FMU Import.
  2. Units on the Y-axis for plots
  3. Improved selection of objects in the 3D animation viewer
  4. Re-declare components using the drop-down list.

Compatibility Notes🔗

  • The workspace version is updated, if you wish to keep using a workspace with an older version of Impact it is recommended to save a backup before opening it in this version.
  • The default number of workers in the cluster for local installation has been changed from “number of available CPUs” to “half the number of available CPUs” to give a better experience to the default user. For users where this default is not suitable, it is still possible to override this with the environment variable IMPACT_WORKER_COUNT.
  • It is possible to add the ‘requires_compilation’ flag to a custom functions ‘configuration’ function. This will skip compilation when running the custom function if the experiment input is the Modelica class name. Observe that this form of an experiment is not used by the web client yet.


  • Introduce the option to import co-simulation FMUs
  • Added units for the Y-axis of plotted result variables
  • Support changing replaceable short class declared within the current model
  • Custom functions can be specified to receive an experiment instead of an FMU as input
  • Support relative paths in the client
  • For a given case selected from a multi-simulation, the 3D viewer will show the animation for that case.
  • Improved selection of objects in the 3D animation viewer
  • Updated Swagger Base URL based on IMPACT_URL ENV variable


  • Pinned plots should no longer appear in newly duplicated or opened models.
  • Modifiers should not be lost when undoing a redeclaration of a short class to a state when there were modifiers included.
  • Changing an index parameter should require recompilation. Note: This does not work for index parameters used on connectors of outer/inner components.
  • FMU caching was not working for cloned workspaces.
  • The Modelica.Fluid.Examples.PumpingSystem was generating errors in the browser’s JavaScript console during dynamic simulation.
  • Fixed a regression in performance when displaying results on stickies.
  • Fixed errors generated in the browser’s JavaScript console when deleting a model from the Workspace package with a pinned plot.
  • Fixed ‘Internal Server Error’ thrown sometimes when deleting a top-level model after simulation.
  • When clicking and dragging in the 3D visualizer the mesh should not get selected/deselected.
  • Fixed malformed URI error during login for users with an id containing åäö.
  • Fixed HTTP 200 response when trying to download a non-existing library.
  • DynamicSelect was only showing the visualization for the first case of a steady state multi-simulation.