# combined 3D graphics with no interface

I'd like to combine several 3D graphics, but the interface, indicated by the arrow in the figure attached between them is alway present. How to eliminate it? Thanks in advance.

Here is my example:

  Graphics3D[{
{EdgeForm[None], Opacity[0.1], Gray,
Cylinder[{{0, 0, 0}, {0, 2, 0}}, 0.5]},
{EdgeForm[None], CapForm["Butt"], Opacity[0.1], Gray,
Tube[{{0, 2, 0}, {0, 3, 0}}, {0.5, 0.2}]},

}, ViewPoint -> {0.8677796780444739, 2.2396029175520074,
2.383513625315694},
ViewVertical -> {-2.366747875495254, -0.028635050478789906,
1.8415006920431496}, Boxed -> False]


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My guess is that this is not possible using Cylinder or Tube primitives. BTW running your code produces a different image than the one you posted. –  Yves Klett Mar 18 at 9:47
@YvesKlett, you mean the arrow that I added using mspaint? –  yulinlinyu Mar 18 at 9:52
Not the arrow, but the right part is also a regular cylinder, and not a truncated cone. Interestingly, this is done by EdgeForm["Butt"]. Without it, the object shows correctly as a cone (though with a rounded end). –  István Zachar Mar 18 at 10:05
@YvesKlett,@István Zachar, my figure is obtained in Ver. 8.0. It shows differently in ver.9, as is pointed out by István Zachar. –  yulinlinyu Mar 18 at 10:50
@YvesKlett,@István Zachar, I think it is a bug for ver.9.0. You can see the same case in the documents by searching "Cone" in the help browser, and entering "Properties & relations". –  yulinlinyu Mar 18 at 10:55
show 1 more comment

Or perhaps you want this (two tubes):

Graphics3D[{
EdgeForm[None],
CapForm[None],
Opacity[0.1],
Gray,
Tube[{{0, 0, 0}, {0, 2, 0}}, 0.5],
Tube[{{0, 2, 0}, {0, 3, 0}}, {0.5, 0.2}]
},
ViewPoint -> {0.86, 2.2, 2.3},
ViewVertical -> {-2.3, 0.0, 1.8},
Boxed -> False]


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Code or it didn´t happen :-P –  Yves Klett Mar 18 at 15:14
OK, you caught me red-handed... –  cormullion Mar 18 at 15:20
Why not a single tube? Tube[{{0, 0, 0}, {0, 2, 0}, {0, 3, 0}}, {0.5, 0.5, 0.2}] –  Simon Woods Mar 18 at 15:49
@Simon Woods, yes, it is the simplest way. –  yulinlinyu Mar 19 at 2:45