You can make them by hand using wrappers for different programming languages, manual implementation, or use a SDK (like fmiCpp). Using a SDK you avoid reimplementing the common functions. It is also possible to make them from tools. Several modelling tools support exporting a simulation model to an FMU. Have a look here for an overview of the different tools that support the FMI standard.
No, but we have developed some models that are available on our github. Feel free to try them out.
Yes! OSP is an open-source computing and software development platform for developing FMU based simulators, running FMU based co-simulations and verifying connections between FMUs.
The core of the platform is a set of software libraries and tools that you can use to build your own simulator. The platform also provides two reference simulator implementations: a web based demo application and command line application. For more information see Software.
We recommend that you have a look in our documentation page.