I found that Industry Foundation Classes (IFC) (Tech Preview) [IFC_API] Reader in FME 2024 cannot reader IfcOpeningElement features and non-subtracted wall, slab etc. features.
In some cases it's essential to read IfcOpeningEelement features as simple solid geometries and non-subtracted features.
It would be nice if the [IFC_API] reader would have parameters equivalent to the "Subtract Openging Geometries" parameter in the current Industry Foundation Class STEP/XML Files (IFC) reader.