Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See page_maxonapi_getting_started_foundations_cinema_parameters.
Parameter: Subdivision U
LOFTOBJECT_SUBX
Parameter: Subdivision V
LOFTOBJECT_SUBY
Parameter: Per Segment
LOFTOBJECT_ADAPTIVEY
Parameter: Isoparm Subdivision U
LOFTOBJECT_ISOPARM
Parameter: Organic Form
LOFTOBJECT_ORGANIC
Parameter: Loop
LOFTOBJECT_CLOSEY
Parameter: Linear Interpolation
LOFTOBJECT_LINEAR
Parameter: Adapt UV
LOFTOBJECT_FITUV
Parameter: Reverse Normals
LOFTOBJECT_FLIPNORMALS