立方体模数截面:梯形截面的构造与几何关系
几何画板及绘图内容加载中,请稍等……
本范例演示在立方体内部进行“模数分区/分段取点”后形成的梯形截面效果,并强调其由对称与中点/连线关系所决定的几何约束。核心数学概念包括:立体几何中的截面、平面与多边形的交构成、相似/全等与对称性(通过镜像/旋转/平移保持结构)、中点与向量定位、以及在三维坐标中使用直线/线段交点来确定关键顶点。作图要点:基于构造摘要使用了 Circle、Point、Rotate、Cube、Midpoint、Polygon、Vector、Sequence、Line、Segment、Translate、Intersect、Mirror;以 Cube 生成立方体,再用 Point、Sequence、Vector 确定截面顶点位置,利用 Midpoint 取中点并用 Line/Segment 形成截线;通过 Intersect 得到截面多边形的关键交点,最后用 Polygon 生成梯形轮廓,并借助 Rotate/Translate/Mirror 展示由对称变换得到的对应结构。适合中学阶段的立体几何探究、竞赛几何的辅助可视化学习,以及教师进行“截面构型与对称性”教学演示。
GeoGebra 命令及参数
Circle(O, r, xOyPlane) → cPoint(c) → A1Rotate(A1, π / 2, O) → A2Cube(A1, A2, zAxis) → a, A3, caraBCGF, caraCDHG, caraEFGH, aristaAD_1, aristaAB, aristaBC_1, aristaCD, aristaAE_1, aristaDH, arista, A4, aristaEF, aristaBF, aristaFG_1, aristaCG_1, aristaGH_1, A5, A6, A7, A8, caraABCD, caraADHE, caraABFEMidpoint(A4, A1) → B8Midpoint(A8, A5) → BDMidpoint(A2, A3) → B6Polygon(A4, BD, A6, B6) → c3, a4, g_1, a6, h_1Polygon(A7, BD, A1, B6) → c2, q, s, e, f_1Vector(A1, BD) → u2Midpoint(A1, A2) → B5Midpoint(O, B5) → AMidpoint(A1, A7) → centroPolygon(A1, BD, centro, A) → c8, l_4, m_4, n_4, a_5Point(n_4) → DVector(A2, B8) → u3Sequence(Max[0, Min[1, t - s]], s, 0, 6) → slMidpoint(A4, A8) → B4Midpoint(A6, A2) → B2Line(A5, A3) → kSegment(A7, A1) → hMidpoint(A1, A5) → B1Midpoint(A3, A7) → B3Midpoint(A3, A4) → B7Midpoint(A5, A6) → BAMidpoint(A6, A7) → BBMidpoint(A7, A8) → BCMidpoint(A1, A6) → O1Midpoint(A2, A7) → O2Midpoint(A3, A8) → O3Midpoint(A8, A1) → O4Midpoint(A5, A7) → O5Vector(A2, B8) → u1Polygon(A8, B8, A2, BB) → c1, a_1, b_1, c_1, d_1Polygon(A4, BD, A6, B6) → c3_1, e_1, f_2, g_2, h_2Translate(c1, u1) → c1'Polygon(A7, BD, A1, B6) → c2_1, f, g, i, jTranslate(c3, u3) → c3'Translate(c2, u2) → c2'Translate(c1', Vector[((-sl(1)) * u1)]) → c1''Translate(c2', Vector[((-sl(2)) * u2)]) → c2''Translate(c3', Vector[((-sl(3)) * u3)]) → c3''Line(B1, B2) → t_1Polygon(A1, A2, A7, A8) → c4, a1, p_2, a7, q_2Translate(c4, u4) → c4'Translate(c4', Vector[((-sl(4)) * u4)]) → c4''Intersect(a_1, e_1) → C1Intersect(c_1, g_2) → C2Polygon(A8, C1, BD, A1, A4) → p1, k_2, l_2, bd, m_2, n_2Intersect(d_1, f) → C3Polygon(A8, C3, A7) → t3, r_2, s_2, t_2Polygon(A8, C3, centro, C1) → c10, b_2, e_2, f_3, g_3Polygon(C3, A7, B6, centro) → c11, h_3, i_3, b6, j_3Polygon(A7, B6, A3) → t4, k_3, l_3, m_3Polygon(A3, A7, A8, A4) → c12, n_3, p_3, q_3, r_3Point(r_3) → BPolygon(A2, A3, B, A1, A) → p2, s_3, t_3, b_3, a_3, a_4Polygon(A2, C2, B6) → t5, c_3, d_3, e_3Polygon(B6, C2, centro) → t6, f_4, g_4, h_4Polygon(C1, centro, BD) → t7, i_4, j_4, k_4Polygon(A2, D, centro, C2) → c9, l, m, n, pTranslate(ll1, u4) → ll2Translate(ll2, Vector[(v * sl(6))]) → ll3Mirror(ll3, centro) → ll4
AI 绘图提示语参考
绘制一个立方体,并在其中心切出一个梯形截面。首先建立一个立方体,然后在立方体的中心点上找到四个关键点,用这些点构造一个梯形。接着,通过旋转和移动这些梯形,生成四个对称的梯形截面。最后,确保所有梯形截面都与立方体的边相交,形成完整的截面图形。
以上提示语为根据原始绘图命令整理而来,仅供参考。