How to hide a part of a torus. I mean in the following torus

ParametricPlot3D[{ (3 + Cos[v]) Sin[u], (3+ Cos[v]) Cos[u], Sin[v]}, {u, 0, 2 Pi}, {v, 0, 2 Pi}]

I want to hide the shaded part enter image description here

  • $\begingroup$ Try {u, -Pi/8, Pi/8}. Is that what you mean? $\endgroup$ – Rohit Namjoshi Jun 20 '19 at 5:33

Simplest way is to change the u range as suggested by Rohit in comments.

A few additional methods:

Using RegionFunction:

ParametricPlot3D[{(3 + Cos[v]) Sin[u], (3 + Cos[v]) Cos[u], 
  Sin[v]}, {u, -Pi, Pi}, {v, 0, 2 Pi}, 
 RegionFunction -> (-Pi + Pi/16 <= #4 <= Pi - Pi/16 &)]

enter image description here

Using MeshFunctions + Mesh + MeshShading:

ParametricPlot3D[{(3 + Cos[v]) Sin[u], (3 + Cos[v]) Cos[u], 
  Sin[v]}, {u, -Pi, Pi}, {v, 0, 2 Pi}, MeshFunctions -> {#4 &}, 
 Mesh -> {{-Pi + Pi/16, Pi - Pi/16}}, 
 MeshShading -> { Automatic,Opacity[.1], Automatic}, 
 Axes -> False, Boxed -> False]

enter image description here

  • $\begingroup$ Thanks! Can I also remove the frame box and the axes? I mean I only need the torus! $\endgroup$ – user21210 Jun 20 '19 at 5:58
  • $\begingroup$ I actually got another question here. I would like to have the wrapping line (ParametricPlot3D[{Cos[Sqrt[2] t](3 + Cos[t]), Sin[Sqrt[2] t] ( 3+Cos[t]),Sin[t]}, {t, 0, 50}}) only on the shown part of the torus above. Can I do that? Thanks a lot ! $\endgroup$ – user21210 Jun 20 '19 at 6:29
  • 1
    $\begingroup$ @AbdelRahmanAl-Amrat, can think of a quick answer b/c the scales are not the same. $\endgroup$ – kglr Jun 20 '19 at 7:37
  • $\begingroup$ I have tried to modify the picture based on your answer to this question. I am sorry, I thought the idea of doing things in Mathematica is the same always. I asked a new question about animation again including the situation above. If you can help me in answering this new question that would be very great.. Thank you so much! mathematica.stackexchange.com/questions/200699/… $\endgroup$ – user21210 Jun 20 '19 at 21:15

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