Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Keep Bridge Open
USDIMPORTER_KEEPBRIDGEOPEN
Parameter: Target
USDIMPORTER_NODESPACE
Parameter: Cameras
USDIMPORTER_CAMERAS
Parameter: Lights
USDIMPORTER_LIGHTUNITS
Parameter: Geometry
USDIMPORTER_GEOMETRY
Parameter: Normals
USDIMPORTER_NORMALS
Parameter: Phong Angle
USDIMPORTER_PHONG_ANGLE
Parameter: UVs
USDIMPORTER_UV
Parameter: Display Color
USDIMPORTER_DISPLAYCOLOR
Parameter: Materials
USDIMPORTER_MATERIALS