io_usd/description/fusdimporter.hParameters are accessed with cinema::C4DAtom::GetParameter() and cinema::C4DAtom::SetParameter(). See Parameters.
Parameter: Keep Bridge Open
USDIMPORTER_KEEPBRIDGEOPENParameter: Cameras
USDIMPORTER_CAMERASParameter: Geometry
USDIMPORTER_GEOMETRYParameter: Materials
USDIMPORTER_MATERIALSParameter: Instances
USDIMPORTER_INSTANCESParameter: Lights
USDIMPORTER_LIGHTUNITSUSDIMPORTER_LIGHTUNITS_NONEUSDIMPORTER_LIGHTUNITS_NITUSDIMPORTER_LIGHTUNITS_CANDELAUSDIMPORTER_LIGHTUNITS_PERCENTParameter: Normals
USDIMPORTER_GEOMETRY_NORMALSUSDIMPORTER_GEOMETRY_NORMALS_NONEUSDIMPORTER_GEOMETRY_NORMALS_VERTEXUSDIMPORTER_GEOMETRY_NORMALS_PHONGParameter: Phong Angle
USDIMPORTER_GEOMETRY_PHONG_ANGLEParameter: UVs
USDIMPORTER_GEOMETRY_UVParameter: Display Color
USDIMPORTER_GEOMETRY_DISPLAYCOLORParameter: Tracks
USDIMPORTER_ANIMATION_TRSParameter: Clean Tracks
USDIMPORTER_ANIMATION_CLEANTRACKSParameter: Skin
USDIMPORTER_ANIMATION_SKELETAL