io_obj/description/fobjimport2.hParameters are accessed with cinema::C4DAtom::GetParameter() and cinema::C4DAtom::SetParameter(). See Parameters.
Parameter: Splitting
OBJIMPORTOPTIONS_SPLITBYOBJIMPORTOPTIONS_SPLITBY_OBJECTOBJIMPORTOPTIONS_SPLITBY_MATERIALOBJIMPORTOPTIONS_SPLITBY_GROUP_COMBINE_NAME_COLLISIONSOBJIMPORTOPTIONS_SPLITBY_GROUPOBJIMPORTOPTIONS_SPLITBY_ONEOBJECTParameter: Lines
OBJIMPORTOPTIONS_LINESOBJIMPORTOPTIONS_LINES_DEFAULTOBJIMPORTOPTIONS_LINES_CLOSEDOBJIMPORTOPTIONS_LINES_ASPOLYSParameter: UVs
OBJIMPORTOPTIONS_IMPORT_UVSOBJIMPORTOPTIONS_UV_NONEOBJIMPORTOPTIONS_UV_ORIGINALOBJIMPORTOPTIONS_FLIP_UOBJIMPORTOPTIONS_FLIP_VOBJIMPORTOPTIONS_FLIP_UVParameter: Normals
OBJIMPORTOPTIONS_NORMALSOBJIMPORTOPTIONS_NORMALS_NOIMPORTOBJIMPORTOPTIONS_NORMALS_PHONGTAGOBJIMPORTOPTIONS_NORMALS_VERTEXParameter: Phong Angle
OBJIMPORTOPTIONS_PHONG_ANGLE_DEFAULTParameter: Vertex Colors
OBJIMPORTOPTIONS_VERTEX_COLORParameter: Flip X Axis
OBJIMPORTOPTIONS_POINTTRANSFORM_FLIPXParameter: Swap X and Y Axes
OBJIMPORTOPTIONS_POINTTRANSFORM_SWAPXYParameter: Flip Y Axis
OBJIMPORTOPTIONS_POINTTRANSFORM_FLIPYParameter: Swap X and Z Axes
OBJIMPORTOPTIONS_POINTTRANSFORM_SWAPXZParameter: Flip Z Axis
OBJIMPORTOPTIONS_POINTTRANSFORM_FLIPZParameter: Swap Y and Z Axes
OBJIMPORTOPTIONS_POINTTRANSFORM_SWAPYZParameter: Flip Faces
OBJIMPORTOPTIONS_FLIPFACESParameter: Material
OBJIMPORTOPTIONS_MATERIALOBJIMPORTOPTIONS_MATERIAL_NONEOBJIMPORTOPTIONS_MATERIAL_DEFAULTPEROBJECTOBJIMPORTOPTIONS_MATERIAL_MTLFILEOBJIMPORTOPTIONS_MATERIAL_DEFAULTPERMTLFILEParameter: Default Material
OBJIMPORTOPTIONS_DEFAULTMATERIALOBJIMPORTOPTIONS_DEFAULTMATERIAL_WHITEOBJIMPORTOPTIONS_DEFAULTMATERIAL_RANDOMCOLORSParameter: Material Mix Mode
OBJIMPORTOPTIONS_MATERIAL_MIXMODEOBJIMPORTOPTIONS_MATERIAL_MIXMODE_BLENDOBJIMPORTOPTIONS_MATERIAL_MIXMODE_ADDOBJIMPORTOPTIONS_MATERIAL_MIXMODE_SUBOBJIMPORTOPTIONS_MATERIAL_MIXMODE_MULParameter: Invert Transparency
OBJIMPORTOPTIONS_INVERT_TRANSPARENCYParameter: Sequence
OBJIMPORTOPTIONS_SEQUENCE_ANIMATIONParameter: FPS
OBJIMPORTOPTIONS_SEQUENCE_FPSParameter: Frame Step
OBJIMPORTOPTIONS_SEQUENCE_FRAME_STEPParameter: Shared Material
OBJIMPORTOPTIONS_SEQUENCE_SHARED_MATERIALParameter: PLA Interpolation
OBJIMPORTOPTIONS_SEQUENCE_PLAParameter: Script Console Reporting
OBJIMPORTOPTIONS_REPORT_SCRIPTCONSOLEParameter: Import as UTF-8
OBJIMPORTOPTIONS_ENCODING_UTF8