by 落霜枫舞

椭圆形活动桌面设计（2014年全国建模大赛B题）

by：落霜枫舞

代码：

R = 25; h = 50; CurveFunction[x_] := Sqrt[R^2 - (R - x)^2]; Manipulate[ Block[ {rotateAngle := ArcTan[(\[Lambda] (l - CurveFunction[d/2]) Sin[\[Alpha]])/( CurveFunction[d/2] - CurveFunction[(n - 1/2) d] + \[Lambda] (l - CurveFunction[d/2]) Cos[\[Alpha]])]}, Show[ (*画桌面*) Graphics3D[ Table[Cuboid[{-CurveFunction[(n - 1/2) d], (n - 1) d, 0}, {CurveFunction[(n - 1/2) d], n d, 3}], {n, 1, (2 R)/d}], BaseStyle -> {Opacity[0.5], Cyan}], (*画一侧桌腿*) Graphics3D[ Table[Rotate[ Cuboid[{CurveFunction[(n - 1/2) d], (n - 1) d, 0}, {CurveFunction[(n - 1/2) d] + l - CurveFunction[(n - 1/2) d], n d, 3}], If[rotateAngle < 0, \[Pi] + rotateAngle, rotateAngle], {0, 1, 0}, {CurveFunction[(n - 1/2) d], 0, 0}], {n, 1, (2 R)/d}]], (*画另一侧桌腿*) Graphics3D[ Table[Rotate[ Cuboid[{-CurveFunction[(n - 1/2) d], (n - 1) d, 0}, {-(CurveFunction[(n - 1/2) d] + l - CurveFunction[(n - 1/2) d]), n d, 3}], If[rotateAngle < 0, \[Pi] + rotateAngle, rotateAngle], {0, -1, 0}, {-CurveFunction[(n - 1/2) d], 0, 0}], {n, 1, (2 R)/d}]], (*画一侧钢筋*) Graphics3D[{Black, Opacity[1], Cylinder[{{(l - CurveFunction[d/2]) \[Lambda] Cos[\[Alpha]] + CurveFunction[d/2] + (3 Sin[\[Alpha]])/ 2, -2, -((l - CurveFunction[d/2]) \[Lambda] Sin[\[Alpha]] - ( 3 Cos[\[Alpha]])/ 2)}, {(l - CurveFunction[d/2]) \[Lambda] Cos[\[Alpha]] + CurveFunction[d/2] + (3 Sin[\[Alpha]])/2, 2 R + 2, -((l - CurveFunction[d/2]) \[Lambda] Sin[\[Alpha]] - ( 3 Cos[\[Alpha]])/2)}}]}], (*画另一侧钢筋*) Graphics3D[{Black, Opacity[1], Cylinder[{{-((l - CurveFunction[d/2]) \[Lambda] Cos[\[Alpha]] + CurveFunction[d/2] + (3 Sin[\[Alpha]])/ 2), -2, -((l - CurveFunction[d/2]) \[Lambda] Sin[\[Alpha]] - ( 3 Cos[\[Alpha]])/ 2)}, {-((l - CurveFunction[d/2]) \[Lambda] Cos[\[Alpha]] + CurveFunction[d/2] + (3 Sin[\[Alpha]])/2), 2 R + 2, -((l - CurveFunction[d/2]) \[Lambda] Sin[\[Alpha]] - ( 3 Cos[\[Alpha]])/2)}}]}], (*画阴影*)Graphics3D[{EdgeForm[None], Black, Polygon[{{(l - CurveFunction[d/2]) Cos[\[Alpha]] + CurveFunction[d/2] + 3 Sin[\[Alpha]], 0, -h}, {(l - CurveFunction[d/2]) Cos[\[Alpha]] + CurveFunction[d/2] + 3 Sin[\[Alpha]], 2 R, -h}, {-((l - CurveFunction[d/2]) Cos[\[Alpha]] + CurveFunction[d/2] + 3 Sin[\[Alpha]]), 2 R, -h}, {-((l - CurveFunction[d/2]) Cos[\[Alpha]] + CurveFunction[d/2] + 3 Sin[\[Alpha]]), 0, -h}}]}], Boxed -> False ] ], {{\[Alpha], ArcSin[h/(l - CurveFunction[d/2])], "桌腿张角"}, 0, ArcSin[h/(l - CurveFunction[d/2])]}, {{\[Lambda], 0.5, "钢筋位置"}, 0, 1}, {{d, 2.5, "木条宽度"}, 0, 10}, {{l, 60, "桌脚长度"}, h + CurveFunction[d/2], 200}]

谢谢落叶枫舞极快的回应，含蓄又热情的说~~~~

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