Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See page_maxonapi_getting_started_foundations_cinema_parameters.
Parameter: Subdivision U
LOFTOBJECT_SUBXParameter: Subdivision V
LOFTOBJECT_SUBYParameter: Per Segment
LOFTOBJECT_ADAPTIVEYParameter: Isoparm Subdivision U
LOFTOBJECT_ISOPARMParameter: Organic Form
LOFTOBJECT_ORGANICParameter: Loop
LOFTOBJECT_CLOSEYParameter: Linear Interpolation
LOFTOBJECT_LINEARParameter: Adapt UV
LOFTOBJECT_FITUVParameter: Reverse Normals
LOFTOBJECT_FLIPNORMALS