Ko te whirihoranga arai o te Pokapū Huri (VMC) he take matua mō tana āhua kinematic, e whakatau ana i te rerekētanga o ngā wāhanga ka taea te hanga me te maru hoki i te wā e hangaia ai. Ko te punaha takotoranga ko te VMC 3-arai, e mahi ana i runga i ngā arai tuarangi e toru: te arai X (mauī ki te matau), te arai Y (mua ki te muri), me te arai Z (pūkiore ki raro, e whakahaerehia ana e te upoko pūkete). E pai ana tēnei whirihoranga mō te hanga i ngā wāhanga prismatic i kapi ai te urunga taputapu mai i te tōraro, pērā i te whakamahi i te karuhi rapa, ngā pokapō, ngā parerarua, me ngā mahi piko me te pātene. Ko te hereanga, kia hangaia ētahi atu taha o te wāhanga, me whakaputa anō te wāhanga, e āwhina ana i ngā hapa me te piki ake i te wā mahi. Ka whakatika te VMC 4-arai tēnei e te tāpiritanga o tētahi arai rotary, he A-arai (huri ana i te arai X) i te nuinga o te wā, i te B-arai (huri ana i te arai Y), ka uru ki te tepu mātātoko. Mā konei ka taea te whirihora i te wāhanga ki ētahi tūranga kona e tohua ana, ka taea ai te hanga i ngā taha e tāwhai nei kāore he whakaputa anō. He pai tēnei mō ngā wāhanga e hiahiatia ana ngā āhuatanga ki ō rātou taha, i te hanga tonu i ngā āhuatanga puipui. Ko te taumata teitei o te hangarau VMC ko te mātā 5-arai, e rua ngā arai huringa e taea ai te nuku atu i ngā arai tuarangi e toru. Ko ngā whirihoranga noa ko te tepu arawhata (ngā arai A me C) i te upoko hurihuri (ngā arai B me C). Mā tēnei nukunga 5-arai e taea ai te pupuri i te takotoranga taimana, pai rawa atu ki te mata wāhanga. He huringa nui tēnei, e taea ai te hanga i ngā mata hahau, hahau, te hanga i ngā rango hohonu mā te whakamahi i ngā taputapu poto ake, kikii ake, me te whakaoti i ngā wāhanga i tētahi tūranga anake, ka wehe i ngā hapa huinga me te heke i te wā hanga katoa. Nō reira ko te tau arai he whakaritenga matua, e piki haere ana te noho whānuitanga āhuahua o te mātā me te uara hoki mō te hanga i ngā wāhanga rerekē, tikangia teitei.
Kua rite kē te kapa hokohoko mātua ki te āwhina i a koe.