From FreeCAD Documentation
- Extrusions: Checks that all BIM objects are linear extrusions
- Standard cases: Checks that all walls and structural elements are standard cases, as defined by the IFC schema
- Tiny lines: Checks that no line segment in the model is smaller than 1/32", the minimum length that Revit is able to manage...
- IfcRectangleProfileDef: Checks that the option to export rectangular profiles as IfcRectangleProfileDef is disabled, because Revit (yes, them again) is unable to import that entity.