Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Create N-gon
MDATA_UNTRIANGULATE_NGONS_DESCParameter: Flatness Angle
MDATA_UNTRIANGULATE_ANGLE_DESCParameter: Angle
MDATA_UNTRIANGULATE_ANGLE_RAD_DESCParameter: Internal Angle
MDATA_UNTRIANGULATE_USE_ANGLE_DERIVATIONParameter: Angle
MDATA_UNTRIANGULATE_ANGLE_DERIVATIONParameter: Alignment Angle
MDATA_UNTRIANGULATE_USE_ALIGNMENT_DERIVATIONParameter: Angle
MDATA_UNTRIANGULATE_ALIGNMENT_DERIVATIONParameter: Keep UV Boundary
MDATA_UNTRIANGULATE_RESPECTUVBOUNDARYParameter: Keep Phong Edge Breaks
MDATA_UNTRIANGULATE_RESPECTSHADINGBREAKSParameter: Keep Mesh Attributes
MDATA_UNTRIANGULATE_RESPECTPOLYATTRIBUTES