Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See page_maxonapi_getting_started_foundations_cinema_parameters.
Parameter: Fix Tension
TENSIONTAG_FIX
Parameter: Mode
TENSIONTAG_MODE
Parameter: Clamped
TENSIONTAG_CLAMPED
Parameter: Amount
TENSIONTAG_AMOUNT
Parameter: Fold Map
TENSIONTAG_FOLD
Parameter: Make Map
TENSIONTAG_MAKEFOLD
Parameter: Stretch Map
TENSIONTAG_STRETCH
Parameter: Make Map
TENSIONTAG_MAKESTRETCH
Parameter: Selection Tag
TENSIONTAG_SELECTION