莫比烏斯帶,又被譯作:莫比斯環,梅比斯環或麥比烏斯帶.是一種拓撲學結構,它只有一個面(表面),和一個邊界.即它的正反兩面在同一個曲面上,左右兩個邊在同一條曲線上.看它的名字很洋氣,聽它的特征很玄乎,實際上實現起來很容易,就是將一個紙條擰一下,然后粘起兩頭,所生成的帶.公元1858年,德國數學家莫比烏斯(Mobius,1790~1868)發現:把一根紙條扭轉180°后,兩頭再粘接起來做成的紙帶圈,具有魔術般的性質。普通紙帶具有兩個面(即雙側曲面),一個正面,一個反面,兩個面可以塗成不同的顏色;而這樣的紙帶只有一個面(即單側曲面),一只小蟲可以爬遍整個曲面而不必跨過它的邊緣。這種紙帶被稱為“莫比烏斯帶”。
下面將展示幾種莫比烏斯帶的生成算法和切圖,使用自己定義語法的腳本代碼生成數學圖形.相關軟件參見:數學圖形可視化工具,該軟件免費開源.
(1)
vertices = D1:160 D2:80 u = from 0 to (2*PI) D1 v = from -1 to 1 D2 a = sin(u) b = cos(u) c = sin(u/2) d = cos(u/2) r = 5.0 m = 0.2 x = r*(1 + v*m*d)*b y = r*(1 + v*m*d)*a z = r*v*m*c
(2)
vertices = D1:160 D2:80 u = from 0 to (2*PI) D1 v = from -1 to 1 D2 r = 10 x = r*(2 + v*cos(u/2))*cos(u) y = r*(2 + v*cos(u/2))*sin(u) z = r*v*sin(u/2)
(3)
#http://www.mathcurve.com/surfaces/mobius/mobius.shtml vertices = D1:160 D2:80 t = from 0 to (2*PI) D1 r = from 0.6 to 1 D2 s = sin(t) c = cos(t) x = [3*r*r*(r*r - 1) - 6*r*(1 + pow(r, 4))*c + (pow(r, 6) - 1)*(4*c*c - 1)]*s / (3*r*r*r) y = [4*(1 - pow(r, 6))*pow(c,3) - 3*r*(1 + pow(r, 4)) + 3*(r*r - 1)*(1 + pow(r, 4))*c + 6*r*(1 + pow(r, 4))*c*c] / (3*r*r*r) z = 2*s*(r*r - 1)/r
(4)
#http://www.mathcurve.com/surfaces/mobiussurface/mobiussurface.shtml vertices = D1:100 D2:100 u = from (-2) to (2) D1 v = from 0 to (PI*2) D2 a = rand2(1, 10) x = (a + u*cos(v/2))*cos(v) z = (a + u*cos(v/2))*sin(v) y = u*sin(v/2)
(5)
將一個紙條擰一下,然后粘起兩頭會得到莫比烏斯帶,那么擰上N圈呢?
vertices = D1:160 D2:80 u = from 0 to (2*PI) D1 v = from -1 to 1 D2 r = 10 n = 3 x = r*(8 + v*cos(n*u))*cos(u) z = r*(8 + v*cos(n*u))*sin(u) y = r*v*sin(u/2)