Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Hull Value
METABALLOBJECT_THRESHOLD
Parameter: Viewport Subdivision
METABALLOBJECT_SUBEDITOR
Parameter: Render Subdivision
METABALLOBJECT_SUBRAY
Parameter: Exponential Falloff
METABALLOBJECT_EXPONENTIAL
Parameter: Accurate Normals
METABALLOBJECT_ACCURATENORMALS