build descript given associ end navig param assoc start associ end param assoc end associ end param nav navig contain human readibl indic navig descript object assoc start object assoc end nav start model facad model facad type assoc start end model facad model facad type assoc end start start length start translat local action navig anon end end length end translat local action navig anon nav starttoend translat messag format action navig object start end nav endtostart translat messag format action navig object end start translat local action navig bidirect 