Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See page_maxonapi_getting_started_foundations_cinema_parameters.
Parameter: Evaltime
SPIN_INTENS
Parameter: Time
SPIN_TIME
Parameter: Variation
SPIN_TIMEVAR
Parameter: Phase
SPIN_PHASE
Parameter: Variation
SPIN_PHASEVAR
Parameter: Friction
SPIN_FRIC
Parameter: Speed Dependence
SPIN_SPEEDDEP
Parameter: Size Dependence
SPIN_SIZEDEP
Parameter: Axis Type
SPIN_AXISTYPE
Parameter: Axis
SPIN_AXIS
Parameter: Variation
SPIN_AXISVAR
Parameter: On
IN_SPIN_ON
Parameter: Animation Time
IN_SPIN_ATIME