Karfe rufi ne wani ɓangare na kwantena dangane da geometry daban-daban, za a iya raba shi zuwa spherical, oval, farantin, ball crown, cone shell da rufi da sauran nau'ikan, daga cikinsu spherical, oval, farantin, ball crown nau'in rufi da aka sani a matsayin convex rufi. A walda aka raba zuwa juya-juya walda rufi kai, bearing walda rufi kai.
Karfe rufi ne karshen rufi a kan matsin lamba kwantena, shi ne babban matsin lamba sassa na matsin lamba kwantena. Matsayin da aka yi shine aikin hatimi. Na farko ya zama tank matsin lamba kwantena a saman da ƙasa, na biyu shi ne bututun zuwa kan, ba a shirya ya fadada gaba, to, a rufe bututun a cikin nau'i na walda ta amfani da wani rufi. Kayayyakin da suka yi kama da aikin rufi suna da allon makafi da ƙuduri, duk da haka ana iya cire kayayyakin biyu. Ba za a iya cirewa ba bayan an yi walda. Abubuwan haɗin haɗin haɗin haɗin haɗin haɗin haɗin haɗin haɗin haɗin haɗin haɗin haɗin haɗin haɗin haɗin haɗin haɗin haɗin haɗin haɗin haɗin haɗin haɗin haɗin ha