Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Degree U
NURBSSURFACE_UDEGREEParameter: Degree V
NURBSSURFACE_VDEGREEParameter: Points U
NURBSSURFACE_UPOINTCOUNTParameter: Points V
NURBSSURFACE_VPOINTCOUNTParameter: Start U-Parameter
NURBSSURFACE_UMINParameter: End U-Parameter
NURBSSURFACE_UMAXParameter: Start V-Parameter
NURBSSURFACE_VMINParameter: End V-Parameter
NURBSSURFACE_VMAXParameter: Closed U
NURBSSURFACE_UCLOSEDParameter: Closed V
NURBSSURFACE_VCLOSEDParameter: Periodic U
NURBSSURFACE_UPERIODICITYParameter: Periodic V
NURBSSURFACE_VPERIODICITYParameter: Polynomial
NURBSSURFACE_POLYNOMIAL