Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Degree U
NURBSSURFACE_UDEGREE
Parameter: Degree V
NURBSSURFACE_VDEGREE
Parameter: Points U
NURBSSURFACE_UPOINTCOUNT
Parameter: Points V
NURBSSURFACE_VPOINTCOUNT
Parameter: Start U-Parameter
NURBSSURFACE_UMIN
Parameter: End U-Parameter
NURBSSURFACE_UMAX
Parameter: Start V-Parameter
NURBSSURFACE_VMIN
Parameter: End V-Parameter
NURBSSURFACE_VMAX
Parameter: Closed U
NURBSSURFACE_UCLOSED
Parameter: Closed V
NURBSSURFACE_VCLOSED
Parameter: Periodic U
NURBSSURFACE_UPERIODICITY
Parameter: Periodic V
NURBSSURFACE_VPERIODICITY
Parameter: Polynomial
NURBSSURFACE_POLYNOMIAL