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I'm having trouble displaying a hollow cylinder in Mathematica 9. A hollow cylinder looks like this:

hollow cylinder

I tried to use RevolutionPlot3D with a step function. It displays as what I want, but a collection of them in a Show[] is really buggy.

To prevent an X-Y problem, I'll say why I need this shape. I'm making a diagram to show how the integral of a volume of revolution can be approximated by a collection of hollow cylinders, like how the integral of a 1D function can be approximated by a collection of rectangles covering the undergraph.

I want my diagram to look something like this terrible drawing:

enter image description here

A Plot3D bounds the cylinders from above. The whole assembly is shown in a cross section, with one or two cylinders protruding out of the cross section to show what they are supposed to be.

If there is a better way to do this I'm open to that, but if there's some hidden CSG functions in Mathematica that would do the job I would be forever grateful to hear about them

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  • $\begingroup$ Check out Sketch-type graphics with transparency and dashed hidden lines? $\endgroup$
    – user9660
    Commented Apr 25, 2015 at 8:30
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    $\begingroup$ This can be done with Show[{RegionPlot3D[ 2.4 < x^2 + y^2 < 4, {x, -2, 2}, {y, -2, 2}, {z, 0, 2}, Mesh -> None], RegionPlot3D[0.5 < x^2 + y^2 < 2, {x, -2, 2}, {y, -2, 2}, {z, 0, 2}, Mesh -> None]}] pretty easily :) $\endgroup$
    – Öskå
    Commented Apr 25, 2015 at 8:30
  • $\begingroup$ @Öskå make an answer out of it? !Mathematica graphics $\endgroup$
    – chris
    Commented Apr 25, 2015 at 10:26

1 Answer 1

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myData = {{2, 1, #}, {1, 1, 0}} & /@ Table[1/(n + 2) + .2 RandomReal[], {n, 1, 15}];

SectorChart3D[myData, BoxRatios -> {1, 1, 1},
 ColorFunction -> Function[{x, y, z}, Hue[z]],
 ColorFunctionScaling -> False]

enter image description here

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  • $\begingroup$ @blacklemon67 Great... glad to help. If you play around with the ColorFunction, you can likely highlight just one ring (red, say), as in your hand sketch. $\endgroup$ Commented Apr 25, 2015 at 11:14

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