Fact Sheet: Functional Mockup Interface (FMI)

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Short description/
Transmitted information
  • FMI defines an API (Application Programming Interface) and a data file format
  • FMI specification is freely available under a CC-BY-SA (Creative Commons Attribution-ShareAlike 4.0 International) license, header file is under BSD license
Normative document
Version / Release state
  • FMI 3.0
Release date
  • 2022-05-10
Application scope
  • Describe system behaviour of physics, mechatronics, and software
  • Describe causal physical and signal relations
  • Standardized exchange format for behaviour models
  • Multi-physics co-simulation
  • Verification-oriented
Promoting bodies
  • VDA, prostep ivip, JSAE Japan Soc., Modelica Association
  • Modelica Standard, prostep ivip Recommendation
IT Standard classification
  • Interoperability Standard
  • Integration Standard
Data format
  • Text Format (ASCII/XML)
  • Binary Format
  • Compressed (Container-Data)
Additional available resources
  • Many web information resources, e.g.

  • Use Cases, Guidelines, Best Practice Examples

  • Literature (Books, Scientific Papers)

  • Best Practices

  • Smart Systems Engineering (SmartSE), see www.prostep.org

see https://www.youtube.com keywords: functional mockup interface or /watch?v=A-3iIot0fO8

Relevant prostep ivip project groups Smart Systems Engineering Group

Positioning of FMI in V-Model


  • The only standard for exchange of simulation models and co-simulation
  • Needed for interdisciplinary multi-physics and software Simulation (virtual and mixed verification)


  • FMI is based on the ITEA modelisar project which achieved 2012 the ITEA award in silver
  • FMI was supported in 2014 by approximately 60 tools and is currently supported by 141 tools (as of Feb. 2020)
  • FMI is further developed and standardized by the Modelica Association Project FMI

Reached goals:

  • FMI can be used for model exchange and for co-simulation (if implemented by the tool)
  • FMI Cross Check Rules for quality improvement of tool implementation
  • Well-defined development process for further FMI versions (by the Modelica Association Project FMI)
  • Best practice guide for FMI users (developed by the prostep ivip SmartSE project)
  • Endorsed in prostep ivip SmartSE Recommendation V2 (PSI 11 – Smart Systems Engineering - Simulation Model Exchange; avaliable at www.prostep.org)
  • Industrial standard, in industrial use
  • Supported by at least 141 CAE tools (authoring tools, co-simulation platforms, optimization tools, HiL, SiL platforms)
  • Process improvements (templates, guidelines, best practices, contributions to FMI 3.0)

Further goals

  • Further improvement of usability and applications range by new features
  • Extension of FMI cross check from single to connected FMUs in a way that this is consistent with the Modelica Association Project SSP (System Structure and Parameterization of Components for Virtual System Design)

Relevance and Benefit for MBSE

In the context of MBSE FMI is required for behaviour and software behaviour modeling

Risks and Impediments

  • Development efforts need to be split among several FMI versions, slowing down overall adoption rate of the standard
  • Users keep using older versions of the standard; therefore tool vendors have no incentive to implement newer versions for export
  • Releases of non-backward compatible versions cause transition overhead for users, slowing down the adoption of new releases
  • A simulation model using multiple FMU’s from different IT tools may not leverage the full FMI capabilities if one (or more) IT tool(s) do not support all capabilities of the FMI specification. This can lead to unexpected simulation results.