The FMI Steering Committee is happy to announce the preliminary (Alpha) feature list for FMI 3.0. “Preliminary” means that we might be forced to drop some features from that list for the actual release. This list is based on the results of the respective working groups which were discussed at the FMI Design Meeting Nov 2017.

In the unlikely event of unsolvable conflicts between features, the FMI Steering Committee might be forced to again remove or alter features during the merge-phase of all FCPs starting after the release of the Beta feature list. The FMI Steering Committee will make these FCPs available to interested parties on request once their maturity allows dissemination.

General questions about FMI

How are the FMI version numbers defined and what does backwards compatibility of a minor version mean?

According to the FMI development process (link), the version number of an FMI release is defined in the following way:

Note that backward and forward compatibility is with respect to the FMI specification, not with respect to a tool. For example, if FMI 2.1 is backward compatible to FMI 2.0, then every 2.0 FMU must be also a valid 2.1 FMU. As a consequence, a minor version implies restrictions with respect to the previous minor version, especially, but not limited to: (a) new XML elements and attributes, as well as new C API functions must be optional, (b) the argument lists of existing C API functions cannot change (only the meaning of existing arguments can be enhanced, if this is signaled in the modelDescription.xml file with new, optional, XML elements or attributes).

A change to the previous FMI version is called backwards compatible if every FMU compliant with the previous version is also a valid component of the new FMI version. In more detail this means:

Why shall the next FMI release with new features be 3.0 and not 2.1?

After intense struggles to build easy to understand FMI Change Proposals (FCPs), the FMI Steering Committee decided that a point was reached where the cost to keep the FMI 2.1 release backward compatible with 2.0 was too high. Consequently, the decision was reached to rename the next release to “FMI 3.0”.

What are the license and usage conditions for the FMI standard?

Access and use of the FMI standard is free of charge. However, vendors may charge for their tools to support the FMI standard, either by exporting FMUs or by importing FMUs.

To be clear: While the FMI standard is open and free, commercial implementations might not be.

How can I join the FMI Mailing Lists?

I’m a modeler and want to use FMI in my simulation tool

How can I get a first overview on FMI?

Please have a look at the literature page, especially on the overview talks/slides from the 8th, 9th and 10th Modelica Conference

Does my simulation tool support FMI?

Please see the FMI tools page for a list of tools for that tool vendors have announced their support of FMI.

While the FMI project defines cross check rules, the tool vendors carry sole responsibility for their stated FMI support and the provided compatibility results.

Is there a tool vendor independent way to access model information during simulation?

ASAM XIL-MA is a standardized API that allows the access of model parameters, stimulations and simulation results and to control simulation experiments as well. Please see the related ASAM XIL-MA section.

I’m a developer and want to support FMI with my tool

What and in which order should I read/do to get started with FMI technology?

That depends mostly on your background knowledge. We assume here you already have fundamental knowledge of simulation technology (ODE vs. DAE, zero-crossing, state/time events, derivatives etc.):

Does FMI 2.0 support Partial Differential Equations (PDEs)?

There are two kinds of FMI variants: Model Exchange and Co-Simulation.

Model-Exchange FMUs encode ODEs. PDE-support is not planned yet, but the demand for it is increasing.

The second kind, Co-Simulation FMUs, can contain any kind of simulation component because it does not expose states. So as long as you want to simply encapsulate PDEs, this could be done.

But explicitly exposing a PDE to a solver using FMUs is currently not supported.

I added my test FMUs/Cross-Check results but the tools page does not show “green”. Why?

The Cross-Check Rules list a number of conditions before turning an entry “green”. In short:

Please refer to the complete set of rules and notes.

Why are the badge-numbers of the platform-drop-down not adding up to the badge-number in the overview?

The platform-drop-down list contains only platforms the tool has passed the Cross-Check Rules. But the overview lists all FMUs or Cross-Check Results submitted.