I don't think so... from what I can see from video tutorials, they have a sort of generating the 3D model with an user aided process mainly getting info from footprint layers, but with a simplified result. The primary way to integrate MCAD is to load pre-built 3D models.
the best in having FC to build the models is that you have a MCAD environment that can/must be used to check model geometry errors/problems.
The quality of the STEP models may vary a lot depending on the way it get build (sequence/primitives) and on the OCC release.
Mechanical environment requires more deep analysis compared to what is needed for a simple rendering.
The quality of the actual KiCAD MCAD library is a result of a script process to generate models, and a user post process to inspect the result issues of the generated models, including geometry check.
A part of a great developing effort from a great MCAD squad!
The nice thing is that FreeCAD could be used inside KiCAD as a python module ... this is a lot of work because you need to have FC built with the same python resources used inside KiCAD.
A lot of dependencies and moreover a lot of work to use the FC powerful resources inside KiCad.
Anyway normally other EDA sw just are implementing the basis of MCAD inside EDA and are working more on MCAD / ECAD interaction and collaboration, leaving the 'dirt' MCAD work in MCAD native environment.
That is what I would suggest too: do your EDA work in EDA tool and check your mechanical requirements (enclosures, mechanical connections etc.) in a MCAD tool.
1) An option IMO would be to give the user the ability to have some basic 3D full library and the option to load other 3D parts as an user option.
2) An other interesting option IMO would be to have a function to be called inside Kicad or pcbnew to create a full list of needed 3D parts for the user kicad project, then check automatically if those models are already in the users local 3D library and give an option to retrieve with a 'wget' process the missing models from kicad on-line library; finally the downloaded missing models would be placed automatically in the right local folder by the function itself.
For example if you need:
your wget could point to:
and download it directly, placing it to local configured
This would require a very little work to be implemented, compared to create a reliable building MCAD chain in KiCAD, and it would give the user a very little manual work to do and very little internet loading band.
an other happy user here