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I have some points in 3D space that I want to plot as a closed surface. My data is at the bottom of this post.

I tried with ListPlot3D but I got something I don't want:

ListPlot3D[data]

enter image description here

I want it to look like an ellipsoid, a closed surface... with ListPointPlot3D you can see the shape I'm looking for:

enter image description here

Also, if you can help me make the plot a little smooth and maybe a bit transparent, that would be awesome.

Here's the data:

data = {{0., 0., 641.096}, {0., 0., 641.096}, {0., 0., 641.096}, {0., 0., 
  641.096}, {0., 0., 641.096}, {0., 0., 641.096}, {0., 0., 
  641.096}, {0., 0., 641.096}, {0., 0., 641.096}, {0., 0., 
  641.096}, {0., 0., 641.096}, {0., 0., 641.096}, {0., 0., 
  641.096}, {0., 0., 641.096}, {0., 0., 641.096}, {0., 0., 
  641.096}, {0., 0., 641.096}, {0., 0., 641.096}, {0., 0., 
  641.096}, {0., 0., 641.096}, {0., 0., 
  641.096}, {-33.4358, -0.000480308, 500.}, {-32.4323, -10.5379, 
  500.}, {-26.8297, -19.4933, 500.}, {-19.7593, -27.1967, 
  500.}, {-10.91, -33.5769, 500.}, {0.0000221887, -34.9043, 
  500.}, {10.7511, -33.0892, 500.}, {19.4879, -26.8225, 
  500.}, {26.5746, -19.3074, 500.}, {32.4483, -10.5432, 
  500.}, {33.779, -0.000441205, 500.}, {32.4484, 10.543, 
  500.}, {26.5744, 19.3075, 500.}, {19.4878, 26.8226, 500.}, {10.7517,
   33.0889, 500.}, {1.45002*10^-6, 34.9043, 500.}, {-10.9098, 33.577, 
  500.}, {-19.7596, 27.1965, 500.}, {-26.8301, 19.4927, 
  500.}, {-32.4323, 10.5378, 500.}, {-33.4352, 0.000440213, 
  500.}, {-44.8491, -0.0000166531, 400.}, {-41.3575, -13.4379, 
  400.}, {-33.6225, -24.4282, 400.}, {-24.6804, -33.9701, 
  400.}, {-13.8613, -42.6607, 400.}, {-0.000099884, -46.8974, 
  400.}, {13.6798, -42.102, 400.}, {24.3378, -33.4982, 
  400.}, {33.2163, -24.1336, 400.}, {41.0551, -13.3398, 
  400.}, {44.9359, 0.000653844, 400.}, {41.0551, 13.3396, 
  400.}, {33.2166, 24.1332, 400.}, {24.3377, 33.4982, 400.}, {13.68, 
  42.1019, 400.}, {-0.380491, 46.8615, 400.}, {-13.8612, 42.6607, 
  400.}, {-24.6807, 33.9699, 400.}, {-33.6224, 24.4283, 
  400.}, {-41.3572, 13.4384, 400.}, {-44.8703, 0.000712753, 
  400.}, {-51.8426, -0.000612579, 300.}, {-45.947, -14.9298, 
  300.}, {-37.0981, -26.9527, 300.}, {-27.1985, -37.4354, 
  300.}, {-15.3933, -47.3767, 300.}, {0.0000437598, -54.3818, 
  300.}, {15.1401, -46.5957, 300.}, {26.7232, -36.7818, 
  300.}, {36.4393, -26.4748, 300.}, {45.1719, -14.6771, 
  300.}, {51.3474, -0.000353001, 300.}, {45.1719, 14.6771, 
  300.}, {36.4393, 26.4747, 300.}, {26.7239, 36.7812, 300.}, {15.1401,
   46.5957, 300.}, {-0.000270231, 54.3818, 300.}, {-15.3935, 47.3766, 
  300.}, {-27.1984, 37.4355, 300.}, {-37.0975, 26.9534, 
  300.}, {-45.9476, 14.9289, 300.}, {-51.8443, 0.000903271, 
  300.}, {-52.5272, -0.00080404, 200.}, {-45.9094, -14.9169, 
  200.}, {-37.0924, -26.9492, 200.}, {-27.2028, -37.4414, 
  200.}, {-15.3595, -47.2722, 200.}, {-0.000200055, -54.4177, 
  200.}, {15.0395, -46.2864, 200.}, {26.4513, -36.4061, 
  200.}, {35.8459, -26.0443, 200.}, {44.1364, -14.3409, 
  200.}, {49.9257, -0.000704932, 200.}, {44.1365, 14.3407, 
  200.}, {35.8467, 26.0433, 200.}, {26.4509, 36.4065, 200.}, {15.0397,
   46.2862, 200.}, {-0.000269662, 54.4176, 200.}, {-15.3598, 47.272, 
  200.}, {-27.2031, 37.4411, 200.}, {-37.0926, 26.949, 
  200.}, {-45.9095, 14.9167, 200.}, {-52.5279, 0.000854614, 
  200.}, {-43.4968, -0.000346691, 100.}, {-39.8229, -12.9395, 
  100.}, {-32.3192, -23.4813, 100.}, {-23.4945, -32.3374, 
  100.}, {-12.9069, -39.7228, 100.}, {0.0000104505, -42.204, 
  100.}, {12.8085, -39.4206, 100.}, {22.7948, -31.3738, 
  100.}, {30.9405, -22.4796, 100.}, {36.9038, -11.9906, 
  100.}, {39.5753, -0.000198095, 100.}, {36.9038, 11.9908, 
  100.}, {30.9405, 22.4796, 100.}, {22.7945, 31.374, 100.}, {12.8087, 
  39.4206, 100.}, {-0.000468123, 42.2039, 100.}, {-12.9068, 39.7229, 
  100.}, {-23.4949, 32.3371, 100.}, {-32.319, 23.4815, 
  100.}, {-39.823, 12.9393, 100.}, {-43.4973, 0.000701222, 
  100.}, {-25.4858, -0.00042188, 0.}, {-25.0489, -8.13889, 
  0.}, {-22.6818, -16.4793, 0.}, {-15.9412, -21.9417, 
  0.}, {-7.52493, -23.1593, 0.}, {0.0000252356, -23.3718, 
  0.}, {7.47278, -22.9986, 0.}, {15.7025, -21.6126, 
  0.}, {20.0976, -14.6021, 0.}, {21.0782, -6.84871, 0.}, {21.2778, 
  0.000336608, 0.}, {21.0782, 6.84873, 0.}, {20.0977, 14.6019, 
  0.}, {15.7025, 21.6126, 0.}, {7.47262, 22.9986, 0.}, {-0.0000887879,
   23.3719, 0.}, {-7.52488, 23.1592, 0.}, {-15.9413, 21.9416, 
  0.}, {-22.6722, 16.4442, 0.}, {-25.0478, 8.14015, 0.}, {-25.4415, 
  0.0941868, 0.}}
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2
  • 2
    $\begingroup$ Have you tried ConvexHullMesh ? $\endgroup$
    – image_doctor
    Commented Jun 13, 2015 at 20:27
  • $\begingroup$ @image_doctor : Thank you! that's a start. $\endgroup$
    – Ivan
    Commented Jun 13, 2015 at 20:34

3 Answers 3

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2
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For the record, another way to plot the surface generated by these data, and one that allows the smoothness of that surface to be controlled, is via BSplineFunction (the structure of data, since it is composed of equal numbers of points at various z-slices, is really amenable to this).

array = GatherBy[data, Last];
f = BSplineFunction[array, SplineClosed -> {False, True}];
plot1 = ParametricPlot3D[
  f[u, v], {u, 0, 1}, {v, 0, 1}, 
  BoxRatios -> {1, 1, 1}, 
  PlotStyle -> Opacity[0.5] 
 ]

plot1

The function doesn't close the bottom of the surface, but that can easily be done by adding another row at the end of the array:

array2 = Append[array, {0., 0., array[[-1, 1, 3]] - 0.0001} & /@ Range[Length@Last@array]];
g = BSplineFunction[array2, SplineClosed -> {False, True}];
plot2 = ParametricPlot3D[
  g[u, v], {u, 0, 1}, {v, 0, 1},
  BoxRatios -> {1, 1, 1},
  PlotStyle -> Opacity[0.5]
 ]

plot2

The smoothness of the surface can be controlled by SplineDegree (and SplineKnots and SpineWeight). The easy example:

h = BSplineFunction[array2, SplineClosed -> {False, True}, SplineDegree -> 1];
plot3 = ParametricPlot3D[
  h[u, v], {u, 0, 1}, {v, 0, 1}, 
  BoxRatios -> {1, 1, 1}, 
  PlotStyle -> Opacity[0.5] 
 ]

plot3

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1
  • $\begingroup$ @Virgil very nice answer+1 :) $\endgroup$
    – ubpdqn
    Commented Jun 14, 2015 at 23:37
4
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To deal with second part:

ch = ConvexHullMesh[data];
Manipulate[
 With[{rp = 
    RegionPlot3D[ch, MeshFunctions -> (#3 &), Mesh -> {{p}}, 
     MeshStyle -> {Red, Thick}, ImageSize -> 150]}, 
  Row[{rp, Graphics[{EdgeForm[{Red, Thick}], FaceForm[LightOrange], 
      Polygon[(rp[[1, 1]][[First@
            Cases[rp, Line[x__] :> x, Infinity]]])[[All, {1, 2}]]]}, 
     PlotRange -> Table[{-55, 55}, {2}]]}]], {p, 1, 600, 
  Appearance -> "Labeled"}]

enter image description here

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4
$\begingroup$

Use ConvexHullMesh on the raw data.

 ConvexHullMesh[data]

enter image description here

Graphics[Line[Select[data, #[[3]] == 400 &][[All, {1, 2}]]]]

enter image description here

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3
  • $\begingroup$ Thank you! Any way I can create a ContourPlot at, say, z = 400? $\endgroup$
    – Ivan
    Commented Jun 14, 2015 at 1:12
  • $\begingroup$ @David G. Stork Pretty! $\endgroup$
    – image_doctor
    Commented Jun 14, 2015 at 10:52
  • $\begingroup$ @Ivan See the revised solution. A note: On this forum it is considered bad form to ask a question, get a complete and correct solution, and then ask a followup question rather than accepting the correct solution to your original question. $\endgroup$
    – David G. Stork
    Commented Jun 14, 2015 at 13:14

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