Hi Eikejmaas,
What version or Rhino & Revit are you referring to?
When creating a family there is an option to determine Work-Plane based or not in the template
Rhino.Inside.Revit needs to conform to the Revit API tolerances for Geometry, if the Geometry can not be imported as native Revit geometry it will fall back to less desired import methods (mesh), which wouldn’t be eligible for the ‘Floors from Mass’ Revit UI function.
If you are having issues with particular imports not showing up feel free to post the Geometry and we can take a look.
