thinking_particles/description/op_objectshape.hParameters are accessed with cinema::C4DAtom::GetParameter() and cinema::C4DAtom::SetParameter(). See Parameters.
Parameter: Object
OSHAPE_OBJECTParameter: Bounding Radius
OSHAPE_RADIUSParameter: Render Instance
OSHAPE_RENDERINSTANCEParameter: On
IN_OSHAPE_ONParameter: Animation Time
IN_OSHAPE_ATIME